Add const in five places to move 1 KiB to .rdata

xmlUnicodeBlocks is logically const but was not marked as such. This
fixes that, thus moving it to the read-only data segment.
diff --git a/xmlunicode.c b/xmlunicode.c
index ce6e9a4..6d0a96a 100644
--- a/xmlunicode.c
+++ b/xmlunicode.c
@@ -29,14 +29,14 @@
 } xmlUnicodeRange;
 
 typedef struct {
-    xmlUnicodeRange *table;
+    const xmlUnicodeRange *table;
     int		    numentries;
 } xmlUnicodeNameTable;
 
 
 static xmlIntFunc *xmlUnicodeLookup(xmlUnicodeNameTable *tptr, const char *tname);
 
-static xmlUnicodeRange xmlUnicodeBlocks[] = {
+static const xmlUnicodeRange xmlUnicodeBlocks[] = {
   {"AegeanNumbers", xmlUCSIsAegeanNumbers},
   {"AlphabeticPresentationForms", xmlUCSIsAlphabeticPresentationForms},
   {"Arabic", xmlUCSIsArabic},
@@ -945,7 +945,7 @@
 static xmlIntFunc
 *xmlUnicodeLookup(xmlUnicodeNameTable *tptr, const char *tname) {
     int low, high, mid, cmp;
-    xmlUnicodeRange *sptr;
+    const xmlUnicodeRange *sptr;
 
     if ((tptr == NULL) || (tname == NULL)) return(NULL);