Allow an override of MACOSX_DEPLOYMENT_TARGET, so the user can build against a different SDK if desired.

R=mtklein@google.com, bungeman, mtklein

Review URL: https://codereview.chromium.org/138033018

git-svn-id: http://skia.googlecode.com/svn/trunk@13126 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gyp/common_conditions.gypi b/gyp/common_conditions.gypi
index f3caddc..4db0a40 100644
--- a/gyp/common_conditions.gypi
+++ b/gyp/common_conditions.gypi
@@ -348,7 +348,13 @@
         },
         'xcode_settings': {
           'GCC_SYMBOLS_PRIVATE_EXTERN': 'NO',
-          'MACOSX_DEPLOYMENT_TARGET': '10.6', # -mmacos-version-min, passed in environment to ld.
+          'conditions': [
+            [ 'skia_osx_deployment_target==""', {
+              'MACOSX_DEPLOYMENT_TARGET': '10.6', # -mmacos-version-min, passed in environment to ld.
+            }, {
+              'MACOSX_DEPLOYMENT_TARGET': '<(skia_osx_deployment_target)',
+            }],
+          ],
 # trying to get this to work, but it needs clang I think...
 #          'WARNING_CFLAGS': '-Wexit-time-destructors',
           'CLANG_WARN_CXX0X_EXTENSIONS': 'NO',
diff --git a/gyp/common_variables.gypi b/gyp/common_variables.gypi
index 39e37e8..ac57b69 100644
--- a/gyp/common_variables.gypi
+++ b/gyp/common_variables.gypi
@@ -95,7 +95,7 @@
       'skia_chrome_utils%': 1,
       'skia_directwrite%': 0,
       'skia_gpu%': 1,
-      'skia_osx_sdkroot%': '',
+      'skia_osx_deployment_target%': '',
       'skia_profile_enabled%': 0,
       'skia_win_debuggers_path%': '',
       'skia_shared_lib%': 0,
@@ -158,7 +158,7 @@
     'skia_directwrite%': '<(skia_directwrite)',
     'skia_gpu%': '<(skia_gpu)',
     'skia_win_exceptions%': 0,
-    'skia_osx_sdkroot%': '<(skia_osx_sdkroot)',
+    'skia_osx_deployment_target%': '<(skia_osx_deployment_target)',
     'skia_profile_enabled%': '<(skia_profile_enabled)',
     'skia_shared_lib%': '<(skia_shared_lib)',
     'skia_opencl%': '<(skia_opencl)',