Bug 1534321 - Assembly builds for libdav1d on OSX. r=TD-Linux

Differential Revision: https://phabricator.services.mozilla.com/D23111

--HG--
extra : moz-landing-system : lando

media/libdav1d/moz.build

@@ -32,7 +32,7 @@ DEFINES['DAV1D_API'] = ''
 if CONFIG['MOZ_DAV1D_ASM']:
     # Default stack aligment is 16 bytes
     DIRS += ['asm']
-    if CONFIG['OS_TARGET'] == 'WINNT' and CONFIG['CPU_ARCH'] == 'x86_64':
+    if CONFIG['OS_TARGET'] in ('WINNT', 'Darwin') and CONFIG['CPU_ARCH'] == 'x86_64':
          # Update stack aligment to 32 bytes
          if CONFIG['CC_TYPE'] == 'clang':
              CFLAGS += ['-mstack-alignment=32']

toolkit/moz.configure

@@ -445,7 +445,8 @@ def av1(value):
 def dav1d_asm(target, nasm_version):
     if (
             target.os == 'GNU' and target.kernel == 'Linux' and target.cpu in ('x86', 'x86_64') or
-            target.os == 'WINNT' and target.cpu in ('x86', 'x86_64')
+            target.os == 'WINNT' and target.cpu in ('x86', 'x86_64') or
+            target.os == 'OSX' and target.kernel == 'Darwin' and target.cpu == 'x86_64'
        ):
         if nasm_version < '2.13':
             die('nasm 2.13 or greater is required for AV1 support. '