Bug 1896547 - Fix ios build by adding dotprod and crc flags r=media-playback-reviewers,padenot

This patch fixes the iOS build by adding the dotprod and crc flags for
files ending with `neon_dotprod.c` and `arm_crc32.c`. These flags are
copied from build/cmake/cpu.cmake [1].

[1] https://aomedia.googlesource.com/aom/+/8f107273cc641d3d4c260df122a21399b7e46a93/build/cmake/cpu.cmake#18

Differential Revision: https://phabricator.services.mozilla.com/D210584

media/libaom/moz.build

@@ -79,6 +79,10 @@ elif CONFIG['TARGET_CPU'] == 'aarch64' and CONFIG['OS_TARGET'] == 'Darwin':
             SOURCES[f].flags += CONFIG['NEON_FLAGS']
         if f.endswith('neon_i8mm.c'):
             SOURCES[f].flags += CONFIG['NEON_I8MM_FLAGS']
+        if f.endswith('neon_dotprod.c'):
+            SOURCES[f].flags += ['-march=armv8.2-a+dotprod']
+        if f.endswith('arm_crc32.c'):
+            SOURCES[f].flags += ['-march=armv8-a+crc']
 else:
     # Generic C-only configuration
     EXPORTS.aom += files['GENERIC_EXPORTS']