Merge pull request godotengine#1560 from Faless/fix/build_web_cppflags_is_ccflags

[Web/SCons] Use CCFLAGS for SIDE_MODULE option

Author: dsnopek

tools/web.py

@@ -39,7 +39,7 @@ def generate(env):
         env.Append(LINKFLAGS=["-sUSE_PTHREADS=1"])
 
     # Build as side module (shared library).
-    env.Append(CPPFLAGS=["-sSIDE_MODULE=1"])
+    env.Append(CCFLAGS=["-sSIDE_MODULE=1"])
     env.Append(LINKFLAGS=["-sSIDE_MODULE=1"])
 
     # Force wasm longjmp mode.