OSX/scons: introducing and testing an unexported_symbols_list to prevent clashes, todo: cmake

SConstruct

@@ -312,6 +312,9 @@ if env['OURPLATFORM']=='darwin':
         env.Append(LINKFLAGS=['-L'+OSX_OSL_LIBPATH,'-loslcomp','-force_load '+ OSX_OSL_LIBPATH +'/liboslexec.a','-loslquery'])
         env.Append(BF_PROGRAM_LINKFLAGS=['-Xlinker','-force_load','-Xlinker',OSX_OSL_LIBPATH +'/liboslexec.a'])
 
+    # Trying to get rid of eventually clashes, we export some explicite as local symbols		
+    env.Append(LINKFLAGS=['-Xlinker','-unexported_symbols_list','-Xlinker','./source/creator/osx_locals.map'])
+
 if env['WITH_BF_OPENMP'] == 1:
         if env['OURPLATFORM'] in ('win32-vc', 'win64-vc'):
                 env['CCFLAGS'].append('/openmp')

source/creator/osx_locals.map

+## The symbols will be treated as if they were marked as __private_extern__
+## (aka visibility=hidden) and will not be global in the output file
+*boost*