Use .text instead of .rodata on macho

The read only sections are getting stripped on some OS X builds. As a
result, random data is used in place of the intended tables.

Change-Id: I58c18a53e503f093ee268451698c5761e6c32540

third_party/x86inc/README.libvpx

@@ -17,3 +17,4 @@ Catch all elf formats for 'hidden' status and SECTION notes.
 Avoid 'amdnop' when building with nasm.
 Set 'private_extern' visibility for macho targets.
 Copy PIC 'GLOBAL' macros from x86_abi_support.asm
+Use .text instead of .rodata on macho to avoid broken tables in PIC mode.

third_party/x86inc/x86inc.asm.new

@@ -78,8 +78,18 @@
     %define mangle(x) _ %+ x
 %endif
 
+; In some instances macho32 tables get misaligned when using .rodata.
+; When looking at the disassembly it appears that the offset is either
+; correct or consistently off by 90. Placing them in the .text section
+; works around the issue. It appears to be specific to the way libvpx
+; handles the tables.
 %macro SECTION_RODATA 0-1 16
-    SECTION .rodata align=%1
+    %ifidn __OUTPUT_FORMAT__,macho32
+        SECTION .text align=%1
+        fakegot:
+    %else
+        SECTION .rodata align=%1
+    %endif
 %endmacro
 
 %macro SECTION_TEXT 0-1 16