scons: Whenever possible decide what to do based on platform and not compiler.

Because compilers like GCC and Clang are effectively available everywhere
so their presence/absence is seldom conclusive.

Furthermore, all compilers we use now have stdint.h.

Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Reviewed-by: Brian Paul <brianp@vmware.com>

src/gallium/drivers/svga/SConscript

@@ -8,7 +8,6 @@ if env['suncc']:
 	print 'warning: not building svga'
 	Return()
 
-if env['gcc'] or env['clang']:
 env.Append(CPPDEFINES = [
        'HAVE_STDINT_H',
 ])

src/gallium/winsys/svga/drm/SConscript

@@ -4,8 +4,6 @@ env = env.Clone()
 
 env.PkgUseModules('DRM')
 
-if env['gcc'] or env['clang'] or env['icc']:
-    env.Append(CCFLAGS = ['-fvisibility=hidden'])
 env.Append(CPPDEFINES = [
     'HAVE_STDINT_H',
     '-D_FILE_OFFSET_BITS=64',

src/mapi/glapi/SConscript

@@ -52,8 +52,7 @@ for s in mapi_sources:
 #
 # Assembly sources
 #
-if (env['gcc'] or env['clang']) and \
+if env['platform'] not in ('cygwin', 'darwin', 'windows'):
-   env['platform'] not in ('cygwin', 'darwin', 'windows'):
     GLAPI = '#src/mapi/glapi/'
     sources = [GLAPI + 'gen/gl_and_es_API.xml'] + env.Glob(GLAPI + 'gen/*.xml')
 

src/mesa/SConscript

@@ -82,8 +82,7 @@ format_unpack = env.CodeGenerate(
 #
 # Assembly sources
 #
-if (env['gcc'] or env['clang']) and \
+if env['platform'] not in ('cygwin', 'darwin', 'windows', 'haiku'):
-   env['platform'] not in ('cygwin', 'darwin', 'windows', 'haiku'):
     if env['machine'] == 'x86':
         env.Append(CPPDEFINES = [
             'USE_X86_ASM',