update for latest sourcemod

AMBuildScript

@@ -178,7 +178,7 @@ class ExtensionConfig(object):
       '-fvisibility=hidden',
     ]
     cxx.cxxflags += [
-      '-std=c++11',
+      '-std=c++14',
       '-fno-exceptions',
       '-fno-threadsafe-statics',
       '-Wno-non-virtual-dtor',
@@ -266,6 +266,7 @@ class ExtensionConfig(object):
       cxx.linkflags += ['-static-libgcc']
     elif cxx.vendor == 'clang':
       cxx.linkflags += ['-lgcc_eh']
+    cxx.linkflags += ['-static-libstdc++']
 
   def configure_mac(self, cxx):
     cxx.defines += ['OSX', '_OSX', 'POSIX']