scons: Pass -Wno-parentheses-equality to clang for src/lua/ library objects

Step 2/2 in making it possible to build in strict mode with clang 3.3
and scons here.

src/lua/SConscript

@@ -36,6 +36,8 @@ loadlib.cpp
 linit.cpp
 """)
 liblua = env.Library("lua", lua_sources, 
+    # Silence some Clang-specific warnings due to extra parentheses in if statements when comparing.
+    CCFLAGS = ["$CCFLAGS", "clang" in env["CXX"] and "-Wno-parentheses-equality" or []],
     CCCOM = env["CXXCOM"],
     CPPPATH = ["$CPPPATH", Dir(".").srcnode()],
     CPPDEFINES = ["$CPPDEFINES", env["PLATFORM"] != "win32" and "LUA_USE_POSIX" or []])