Bug 1512504 - Don't set __PRETTY_FUNCTION__ on clang-cl. r=froydnj

clang-cl defines it on its own, although the value is slightly different
from __FUNCSIG__ (it doesn't contain the ABI, which doesn't really
matter). We've only been setting it this was on clang-cl by extension of
setting it for msvc.

Depends on D19616

Differential Revision: https://phabricator.services.mozilla.com/D19617

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

dom/media/systemservices/moz.build

@@ -49,8 +49,6 @@ if CONFIG['MOZ_WIDGET_TOOLKIT'] == 'cocoa':
   EXPORTS += ['OSXRunLoopSingleton.h']
 
 if CONFIG['CC_TYPE'] == 'clang-cl':
-    DEFINES['__PRETTY_FUNCTION__'] = '__FUNCSIG__'
-
     # This is intended as a temporary workaround to enable building with VS2015.
     # media\webrtc\trunk\webrtc/base/criticalsection.h(59): warning C4312:
     # 'reinterpret_cast': conversion from 'DWORD' to 'HANDLE' of greater size

dom/media/webrtc/moz.build

@@ -91,4 +91,3 @@ if CONFIG['CC_TYPE'] == 'clang-cl':
         '-wd4312', # This is intended as a temporary hack to support building with VS2015
                    # 'reinterpret_cast': conversion from 'DWORD' to 'HANDLE' of greater size
     ]
-    DEFINES['__PRETTY_FUNCTION__'] = '__FUNCSIG__'

media/webrtc/webrtc.mozbuild

@@ -22,8 +22,5 @@ if CONFIG['MOZ_WEBRTC']:
     elif CONFIG['OS_TARGET'] == 'Android':
         DEFINES['WEBRTC_ANDROID'] = True
 
-    if CONFIG['CC_TYPE'] == 'clang-cl':
-        DEFINES['__PRETTY_FUNCTION__'] = '__FUNCSIG__'
-
     if CONFIG['CC_TYPE'] in ('clang', 'gcc'):
         CXXFLAGS += ['-Wno-error=shadow']