diff --git a/Lib/locale.py b/Lib/locale.py
index fa24829..f7d4d7b 100644
--- a/Lib/locale.py
+++ b/Lib/locale.py
@@ -822,11 +822,15 @@
     'a3':                                   'az_AZ.KOI8-C',
     'a3_az':                                'az_AZ.KOI8-C',
     'a3_az.koic':                           'az_AZ.KOI8-C',
+    'aa_dj':                                'aa_DJ.ISO8859-1',
+    'aa_er':                                'aa_ER.UTF-8',
+    'aa_et':                                'aa_ET.UTF-8',
     'af':                                   'af_ZA.ISO8859-1',
     'af_za':                                'af_ZA.ISO8859-1',
     'am':                                   'am_ET.UTF-8',
     'am_et':                                'am_ET.UTF-8',
     'american':                             'en_US.ISO8859-1',
+    'an_es':                                'an_ES.ISO8859-15',
     'ar':                                   'ar_AA.ISO8859-6',
     'ar_aa':                                'ar_AA.ISO8859-6',
     'ar_ae':                                'ar_AE.ISO8859-6',
@@ -850,6 +854,8 @@
     'arabic':                               'ar_AA.ISO8859-6',
     'as':                                   'as_IN.UTF-8',
     'as_in':                                'as_IN.UTF-8',
+    'ast_es':                               'ast_ES.ISO8859-15',
+    'ayc_pe':                               'ayc_PE.UTF-8',
     'az':                                   'az_AZ.ISO8859-9E',
     'az_az':                                'az_AZ.ISO8859-9E',
     'az_az.iso88599e':                      'az_AZ.ISO8859-9E',
@@ -857,17 +863,25 @@
     'be@latin':                             'be_BY.UTF-8@latin',
     'be_by':                                'be_BY.CP1251',
     'be_by@latin':                          'be_BY.UTF-8@latin',
+    'bem_zm':                               'bem_ZM.UTF-8',
+    'ber_dz':                               'ber_DZ.UTF-8',
+    'ber_ma':                               'ber_MA.UTF-8',
     'bg':                                   'bg_BG.CP1251',
     'bg_bg':                                'bg_BG.CP1251',
+    'bho_in':                               'bho_IN.UTF-8',
+    'bn_bd':                                'bn_BD.UTF-8',
     'bn_in':                                'bn_IN.UTF-8',
+    'bo_cn':                                'bo_CN.UTF-8',
     'bo_in':                                'bo_IN.UTF-8',
     'bokmal':                               'nb_NO.ISO8859-1',
     'bokm\xe5l':                            'nb_NO.ISO8859-1',
     'br':                                   'br_FR.ISO8859-1',
     'br_fr':                                'br_FR.ISO8859-1',
+    'brx_in':                               'brx_IN.UTF-8',
     'bs':                                   'bs_BA.ISO8859-2',
     'bs_ba':                                'bs_BA.ISO8859-2',
     'bulgarian':                            'bg_BG.CP1251',
+    'byn_er':                               'byn_ER.UTF-8',
     'c':                                    'C',
     'c-french':                             'fr_CA.ISO8859-1',
     'c.ascii':                              'C',
@@ -884,10 +898,13 @@
     'cextend':                              'en_US.ISO8859-1',
     'chinese-s':                            'zh_CN.eucCN',
     'chinese-t':                            'zh_TW.eucTW',
+    'crh_ua':                               'crh_UA.UTF-8',
     'croatian':                             'hr_HR.ISO8859-2',
     'cs':                                   'cs_CZ.ISO8859-2',
     'cs_cs':                                'cs_CZ.ISO8859-2',
     'cs_cz':                                'cs_CZ.ISO8859-2',
+    'csb_pl':                               'csb_PL.UTF-8',
+    'cv_ru':                                'cv_RU.UTF-8',
     'cy':                                   'cy_GB.ISO8859-1',
     'cy_gb':                                'cy_GB.ISO8859-1',
     'cz':                                   'cs_CZ.ISO8859-2',
@@ -904,23 +921,30 @@
     'de_de':                                'de_DE.ISO8859-1',
     'de_lu':                                'de_LU.ISO8859-1',
     'deutsch':                              'de_DE.ISO8859-1',
+    'doi_in':                               'doi_IN.UTF-8',
     'dutch':                                'nl_NL.ISO8859-1',
     'dutch.iso88591':                       'nl_BE.ISO8859-1',
+    'dv_mv':                                'dv_MV.UTF-8',
+    'dz_bt':                                'dz_BT.UTF-8',
     'ee':                                   'ee_EE.ISO8859-4',
     'ee_ee':                                'ee_EE.ISO8859-4',
     'eesti':                                'et_EE.ISO8859-1',
     'el':                                   'el_GR.ISO8859-7',
+    'el_cy':                                'el_CY.ISO8859-7',
     'el_gr':                                'el_GR.ISO8859-7',
     'el_gr@euro':                           'el_GR.ISO8859-15',
     'en':                                   'en_US.ISO8859-1',
+    'en_ag':                                'en_AG.UTF-8',
     'en_au':                                'en_AU.ISO8859-1',
     'en_be':                                'en_BE.ISO8859-1',
     'en_bw':                                'en_BW.ISO8859-1',
     'en_ca':                                'en_CA.ISO8859-1',
+    'en_dk':                                'en_DK.ISO8859-1',
     'en_gb':                                'en_GB.ISO8859-1',
     'en_hk':                                'en_HK.ISO8859-1',
     'en_ie':                                'en_IE.ISO8859-1',
     'en_in':                                'en_IN.ISO8859-1',
+    'en_ng':                                'en_NG.UTF-8',
     'en_nz':                                'en_NZ.ISO8859-1',
     'en_ph':                                'en_PH.ISO8859-1',
     'en_sg':                                'en_SG.ISO8859-1',
@@ -928,6 +952,7 @@
     'en_us':                                'en_US.ISO8859-1',
     'en_us@euro@euro':                      'en_US.ISO8859-15',
     'en_za':                                'en_ZA.ISO8859-1',
+    'en_zm':                                'en_ZM.UTF-8',
     'en_zw':                                'en_ZW.ISO8859-1',
     'eng_gb':                               'en_GB.ISO8859-1',
     'english':                              'en_EN.ISO8859-1',
@@ -944,6 +969,7 @@
     'es_cl':                                'es_CL.ISO8859-1',
     'es_co':                                'es_CO.ISO8859-1',
     'es_cr':                                'es_CR.ISO8859-1',
+    'es_cu':                                'es_CU.UTF-8',
     'es_do':                                'es_DO.ISO8859-1',
     'es_ec':                                'es_EC.ISO8859-1',
     'es_es':                                'es_ES.ISO8859-1',
@@ -967,8 +993,10 @@
     'fa':                                   'fa_IR.UTF-8',
     'fa_ir':                                'fa_IR.UTF-8',
     'fa_ir.isiri3342':                      'fa_IR.ISIRI-3342',
+    'ff_sn':                                'ff_SN.UTF-8',
     'fi':                                   'fi_FI.ISO8859-15',
     'fi_fi':                                'fi_FI.ISO8859-15',
+    'fil_ph':                               'fil_PH.UTF-8',
     'finnish':                              'fi_FI.ISO8859-1',
     'fo':                                   'fo_FO.ISO8859-1',
     'fo_fo':                                'fo_FO.ISO8859-1',
@@ -983,6 +1011,9 @@
     'french':                               'fr_FR.ISO8859-1',
     'french.iso88591':                      'fr_CH.ISO8859-1',
     'french_france':                        'fr_FR.ISO8859-1',
+    'fur_it':                               'fur_IT.UTF-8',
+    'fy_de':                                'fy_DE.UTF-8',
+    'fy_nl':                                'fy_NL.UTF-8',
     'ga':                                   'ga_IE.ISO8859-1',
     'ga_ie':                                'ga_IE.ISO8859-1',
     'galego':                               'gl_ES.ISO8859-1',
@@ -993,12 +1024,15 @@
     'german':                               'de_DE.ISO8859-1',
     'german.iso88591':                      'de_CH.ISO8859-1',
     'german_germany':                       'de_DE.ISO8859-1',
+    'gez_er':                               'gez_ER.UTF-8',
+    'gez_et':                               'gez_ET.UTF-8',
     'gl':                                   'gl_ES.ISO8859-1',
     'gl_es':                                'gl_ES.ISO8859-1',
     'greek':                                'el_GR.ISO8859-7',
     'gu_in':                                'gu_IN.UTF-8',
     'gv':                                   'gv_GB.ISO8859-1',
     'gv_gb':                                'gv_GB.ISO8859-1',
+    'ha_ng':                                'ha_NG.UTF-8',
     'he':                                   'he_IL.ISO8859-8',
     'he_il':                                'he_IL.ISO8859-8',
     'hebrew':                               'he_IL.ISO8859-8',
@@ -1010,12 +1044,19 @@
     'hr':                                   'hr_HR.ISO8859-2',
     'hr_hr':                                'hr_HR.ISO8859-2',
     'hrvatski':                             'hr_HR.ISO8859-2',
+    'hsb_de':                               'hsb_DE.ISO8859-2',
+    'ht_ht':                                'ht_HT.UTF-8',
     'hu':                                   'hu_HU.ISO8859-2',
     'hu_hu':                                'hu_HU.ISO8859-2',
     'hungarian':                            'hu_HU.ISO8859-2',
+    'hy_am':                                'hy_AM.UTF-8',
+    'hy_am.armscii8':                       'hy_AM.ARMSCII_8',
+    'ia_fr':                                'ia_FR.UTF-8',
     'icelandic':                            'is_IS.ISO8859-1',
     'id':                                   'id_ID.ISO8859-1',
     'id_id':                                'id_ID.ISO8859-1',
+    'ig_ng':                                'ig_NG.UTF-8',
+    'ik_ca':                                'ik_CA.UTF-8',
     'in':                                   'id_ID.ISO8859-1',
     'in_id':                                'id_ID.ISO8859-1',
     'is':                                   'is_IS.ISO8859-1',
@@ -1035,6 +1076,7 @@
     'iu_ca.nunacom8':                       'iu_CA.NUNACOM-8',
     'iw':                                   'he_IL.ISO8859-8',
     'iw_il':                                'he_IL.ISO8859-8',
+    'iw_il.utf8':                           'iw_IL.UTF-8',
     'ja':                                   'ja_JP.eucJP',
     'ja_jp':                                'ja_JP.eucJP',
     'ja_jp.euc':                            'ja_JP.eucJP',
@@ -1050,6 +1092,7 @@
     'ka_ge.georgianacademy':                'ka_GE.GEORGIAN-ACADEMY',
     'ka_ge.georgianps':                     'ka_GE.GEORGIAN-PS',
     'ka_ge.georgianrs':                     'ka_GE.GEORGIAN-ACADEMY',
+    'kk_kz':                                'kk_KZ.ptcp154',
     'kl':                                   'kl_GL.ISO8859-1',
     'kl_gl':                                'kl_GL.ISO8859-1',
     'km_kh':                                'km_KH.UTF-8',
@@ -1058,14 +1101,21 @@
     'ko':                                   'ko_KR.eucKR',
     'ko_kr':                                'ko_KR.eucKR',
     'ko_kr.euc':                            'ko_KR.eucKR',
+    'kok_in':                               'kok_IN.UTF-8',
     'korean':                               'ko_KR.eucKR',
     'korean.euc':                           'ko_KR.eucKR',
     'ks':                                   'ks_IN.UTF-8',
     'ks_in':                                'ks_IN.UTF-8',
+    'ku_tr':                                'ku_TR.ISO8859-9',
     'kw':                                   'kw_GB.ISO8859-1',
     'kw_gb':                                'kw_GB.ISO8859-1',
     'ky':                                   'ky_KG.UTF-8',
     'ky_kg':                                'ky_KG.UTF-8',
+    'lb_lu':                                'lb_LU.UTF-8',
+    'lg_ug':                                'lg_UG.ISO8859-10',
+    'li_be':                                'li_BE.UTF-8',
+    'li_nl':                                'li_NL.UTF-8',
+    'lij_it':                               'lij_IT.UTF-8',
     'lithuanian':                           'lt_LT.ISO8859-13',
     'lo':                                   'lo_LA.MULELAO-1',
     'lo_la':                                'lo_LA.MULELAO-1',
@@ -1076,24 +1126,37 @@
     'lt_lt':                                'lt_LT.ISO8859-13',
     'lv':                                   'lv_LV.ISO8859-13',
     'lv_lv':                                'lv_LV.ISO8859-13',
+    'mag_in':                               'mag_IN.UTF-8',
     'mai':                                  'mai_IN.UTF-8',
     'mai_in':                               'mai_IN.UTF-8',
+    'mg_mg':                                'mg_MG.ISO8859-15',
+    'mhr_ru':                               'mhr_RU.UTF-8',
     'mi':                                   'mi_NZ.ISO8859-1',
     'mi_nz':                                'mi_NZ.ISO8859-1',
     'mk':                                   'mk_MK.ISO8859-5',
     'mk_mk':                                'mk_MK.ISO8859-5',
     'ml':                                   'ml_IN.UTF-8',
     'ml_in':                                'ml_IN.UTF-8',
+    'mn_mn':                                'mn_MN.UTF-8',
+    'mni_in':                               'mni_IN.UTF-8',
     'mr':                                   'mr_IN.UTF-8',
     'mr_in':                                'mr_IN.UTF-8',
     'ms':                                   'ms_MY.ISO8859-1',
     'ms_my':                                'ms_MY.ISO8859-1',
     'mt':                                   'mt_MT.ISO8859-3',
     'mt_mt':                                'mt_MT.ISO8859-3',
+    'my_mm':                                'my_MM.UTF-8',
+    'nan_tw@latin':                         'nan_TW.UTF-8@latin',
     'nb':                                   'nb_NO.ISO8859-1',
     'nb_no':                                'nb_NO.ISO8859-1',
+    'nds_de':                               'nds_DE.UTF-8',
+    'nds_nl':                               'nds_NL.UTF-8',
     'ne_np':                                'ne_NP.UTF-8',
+    'nhn_mx':                               'nhn_MX.UTF-8',
+    'niu_nu':                               'niu_NU.UTF-8',
+    'niu_nz':                               'niu_NZ.UTF-8',
     'nl':                                   'nl_NL.ISO8859-1',
+    'nl_aw':                                'nl_AW.UTF-8',
     'nl_be':                                'nl_BE.ISO8859-1',
     'nl_nl':                                'nl_NL.ISO8859-1',
     'nn':                                   'nn_NO.ISO8859-1',
@@ -1113,10 +1176,15 @@
     'nynorsk':                              'nn_NO.ISO8859-1',
     'oc':                                   'oc_FR.ISO8859-1',
     'oc_fr':                                'oc_FR.ISO8859-1',
+    'om_et':                                'om_ET.UTF-8',
+    'om_ke':                                'om_KE.ISO8859-1',
     'or':                                   'or_IN.UTF-8',
     'or_in':                                'or_IN.UTF-8',
+    'os_ru':                                'os_RU.UTF-8',
     'pa':                                   'pa_IN.UTF-8',
     'pa_in':                                'pa_IN.UTF-8',
+    'pa_pk':                                'pa_PK.UTF-8',
+    'pap_an':                               'pap_AN.UTF-8',
     'pd':                                   'pd_US.ISO8859-1',
     'pd_de':                                'pd_DE.ISO8859-1',
     'pd_us':                                'pd_US.ISO8859-1',
@@ -1131,6 +1199,7 @@
     'posix-utf2':                           'C',
     'pp':                                   'pp_AN.ISO8859-1',
     'pp_an':                                'pp_AN.ISO8859-1',
+    'ps_af':                                'ps_AF.UTF-8',
     'pt':                                   'pt_PT.ISO8859-1',
     'pt_br':                                'pt_BR.ISO8859-1',
     'pt_pt':                                'pt_PT.ISO8859-1',
@@ -1144,6 +1213,9 @@
     'russian':                              'ru_RU.ISO8859-5',
     'rw':                                   'rw_RW.ISO8859-1',
     'rw_rw':                                'rw_RW.ISO8859-1',
+    'sa_in':                                'sa_IN.UTF-8',
+    'sat_in':                               'sat_IN.UTF-8',
+    'sc_it':                                'sc_IT.UTF-8',
     'sd':                                   'sd_IN.UTF-8',
     'sd_in':                                'sd_IN.UTF-8',
     'se_no':                                'se_NO.UTF-8',
@@ -1154,8 +1226,10 @@
     'sh_hr.iso88592':                       'hr_HR.ISO8859-2',
     'sh_sp':                                'sr_CS.ISO8859-2',
     'sh_yu':                                'sr_RS.UTF-8@latin',
+    'shs_ca':                               'shs_CA.UTF-8',
     'si':                                   'si_LK.UTF-8',
     'si_lk':                                'si_LK.UTF-8',
+    'sid_et':                               'sid_ET.UTF-8',
     'sinhala':                              'si_LK.UTF-8',
     'sk':                                   'sk_SK.ISO8859-2',
     'sk_sk':                                'sk_SK.ISO8859-2',
@@ -1165,12 +1239,17 @@
     'slovak':                               'sk_SK.ISO8859-2',
     'slovene':                              'sl_SI.ISO8859-2',
     'slovenian':                            'sl_SI.ISO8859-2',
+    'so_dj':                                'so_DJ.ISO8859-1',
+    'so_et':                                'so_ET.UTF-8',
+    'so_ke':                                'so_KE.ISO8859-1',
+    'so_so':                                'so_SO.ISO8859-1',
     'sp':                                   'sr_CS.ISO8859-5',
     'sp_yu':                                'sr_CS.ISO8859-5',
     'spanish':                              'es_ES.ISO8859-1',
     'spanish_spain':                        'es_ES.ISO8859-1',
     'sq':                                   'sq_AL.ISO8859-2',
     'sq_al':                                'sq_AL.ISO8859-2',
+    'sq_mk':                                'sq_MK.UTF-8',
     'sr':                                   'sr_RS.UTF-8',
     'sr@cyrillic':                          'sr_RS.UTF-8',
     'sr@latn':                              'sr_CS.UTF-8@latin',
@@ -1195,12 +1274,17 @@
     'sv':                                   'sv_SE.ISO8859-1',
     'sv_fi':                                'sv_FI.ISO8859-1',
     'sv_se':                                'sv_SE.ISO8859-1',
+    'sw_ke':                                'sw_KE.UTF-8',
+    'sw_tz':                                'sw_TZ.UTF-8',
     'swedish':                              'sv_SE.ISO8859-1',
+    'szl_pl':                               'szl_PL.UTF-8',
     'ta':                                   'ta_IN.TSCII-0',
     'ta_in':                                'ta_IN.TSCII-0',
     'ta_in.tscii':                          'ta_IN.TSCII-0',
     'ta_in.tscii0':                         'ta_IN.TSCII-0',
+    'ta_lk':                                'ta_LK.UTF-8',
     'te':                                   'te_IN.UTF-8',
+    'te_in':                                'te_IN.UTF-8',
     'tg':                                   'tg_TJ.KOI8-C',
     'tg_tj':                                'tg_TJ.KOI8-C',
     'th':                                   'th_TH.ISO8859-11',
@@ -1208,23 +1292,31 @@
     'th_th.tactis':                         'th_TH.TIS620',
     'th_th.tis620':                         'th_TH.TIS620',
     'thai':                                 'th_TH.ISO8859-11',
+    'ti_er':                                'ti_ER.UTF-8',
+    'ti_et':                                'ti_ET.UTF-8',
+    'tig_er':                               'tig_ER.UTF-8',
+    'tk_tm':                                'tk_TM.UTF-8',
     'tl':                                   'tl_PH.ISO8859-1',
     'tl_ph':                                'tl_PH.ISO8859-1',
     'tn':                                   'tn_ZA.ISO8859-15',
     'tn_za':                                'tn_ZA.ISO8859-15',
     'tr':                                   'tr_TR.ISO8859-9',
+    'tr_cy':                                'tr_CY.ISO8859-9',
     'tr_tr':                                'tr_TR.ISO8859-9',
     'ts':                                   'ts_ZA.ISO8859-1',
     'ts_za':                                'ts_ZA.ISO8859-1',
     'tt':                                   'tt_RU.TATAR-CYR',
     'tt_ru':                                'tt_RU.TATAR-CYR',
     'tt_ru.tatarcyr':                       'tt_RU.TATAR-CYR',
+    'tt_ru@iqtelif':                        'tt_RU.UTF-8@iqtelif',
     'turkish':                              'tr_TR.ISO8859-9',
+    'ug_cn':                                'ug_CN.UTF-8',
     'uk':                                   'uk_UA.KOI8-U',
     'uk_ua':                                'uk_UA.KOI8-U',
     'univ':                                 'en_US.utf',
     'universal':                            'en_US.utf',
     'universal.utf8@ucs4':                  'en_US.UTF-8',
+    'unm_us':                               'unm_US.UTF-8',
     'ur':                                   'ur_PK.CP1256',
     'ur_in':                                'ur_IN.UTF-8',
     'ur_pk':                                'ur_PK.CP1256',
@@ -1241,16 +1333,23 @@
     'vi_vn.viscii111':                      'vi_VN.VISCII',
     'wa':                                   'wa_BE.ISO8859-1',
     'wa_be':                                'wa_BE.ISO8859-1',
+    'wae_ch':                               'wae_CH.UTF-8',
+    'wal_et':                               'wal_ET.UTF-8',
+    'wo_sn':                                'wo_SN.UTF-8',
     'xh':                                   'xh_ZA.ISO8859-1',
     'xh_za':                                'xh_ZA.ISO8859-1',
     'yi':                                   'yi_US.CP1255',
     'yi_us':                                'yi_US.CP1255',
+    'yo_ng':                                'yo_NG.UTF-8',
+    'yue_hk':                               'yue_HK.UTF-8',
     'zh':                                   'zh_CN.eucCN',
     'zh_cn':                                'zh_CN.gb2312',
     'zh_cn.big5':                           'zh_TW.big5',
     'zh_cn.euc':                            'zh_CN.eucCN',
     'zh_hk':                                'zh_HK.big5hkscs',
     'zh_hk.big5hk':                         'zh_HK.big5hkscs',
+    'zh_sg':                                'zh_SG.GB2312',
+    'zh_sg.gbk':                            'zh_SG.GBK',
     'zh_tw':                                'zh_TW.big5',
     'zh_tw.euc':                            'zh_TW.eucTW',
     'zh_tw.euctw':                          'zh_TW.eucTW',
diff --git a/Misc/NEWS b/Misc/NEWS
index b26316f..8e94cdc 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -156,6 +156,8 @@
 Library
 -------
 
+- Issue #20079: Added locales supported in glibc 2.18 to locale alias table.
+
 - Issue #20218: Added convenience methods read_text/write_text and read_bytes/
   write_bytes to pathlib.Path objects.
 
@@ -1186,6 +1188,9 @@
 Tools/Demos
 -----------
 
+- Issue #20079: The makelocalealias.py script now can parse the SUPPORTED file
+  from glibc sources and supports command line options for source paths.
+
 - Issue #22201: Command-line interface of the zipfile module now correctly
   extracts ZIP files with directory entries.  Patch by Ryan Wilson.
 
diff --git a/Tools/i18n/makelocalealias.py b/Tools/i18n/makelocalealias.py
index 10887ce..ca69daa 100755
--- a/Tools/i18n/makelocalealias.py
+++ b/Tools/i18n/makelocalealias.py
@@ -8,6 +8,7 @@
 """
 import locale
 import sys
+_locale = locale
 
 # Location of the alias file
 LOCALE_ALIAS = '/usr/share/X11/locale/locale.alias'
@@ -51,6 +52,37 @@
         data[locale] = alias
     return data
 
+def parse_glibc_supported(filename):
+
+    with open(filename, encoding='latin1') as f:
+        lines = list(f)
+    data = {}
+    for line in lines:
+        line = line.strip()
+        if not line:
+            continue
+        if line[:1] == '#':
+            continue
+        if '/' not in line:
+            continue
+        line = line.rstrip('\\').rstrip()
+        alias, _, alias_encoding = line.partition('/')
+        # Lower-case locale
+        locale = alias.lower()
+        # Normalize encoding, if given
+        if '.' in locale:
+            lang, encoding = locale.split('.')[:2]
+            encoding = encoding.replace('-', '')
+            encoding = encoding.replace('_', '')
+            locale = lang + '.' + encoding
+        # Add an encoding to alias
+        alias, _, modifier = alias.partition('@')
+        alias = _locale._replace_encoding(alias, alias_encoding)
+        if modifier and not (modifier == 'euro' and alias_encoding == 'ISO-8859-15'):
+            alias += '@' + modifier
+        data[locale] = alias
+    return data
+
 def pprint(data):
     items = sorted(data.items())
     for k, v in items:
@@ -92,8 +124,19 @@
     return errors
 
 if __name__ == '__main__':
+    import argparse
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--locale-alias', default=LOCALE_ALIAS,
+                        help='location of the X11 alias file '
+                             '(default: %a)' % LOCALE_ALIAS)
+    parser.add_argument('--glibc-supported',
+                        help='location of the glibc SUPPORTED locales file')
+    args = parser.parse_args()
+
     data = locale.locale_alias.copy()
-    data.update(parse(LOCALE_ALIAS))
+    if args.glibc_supported:
+        data.update(parse_glibc_supported(args.glibc_supported))
+    data.update(parse(args.locale_alias))
     data = optimize(data)
     print_differences(data, locale.locale_alias)
     print()