scons: Silence MSVC C4351 warning.
scons: Silence MSVC C4351 warning.

It warns about change in MSVC behavior -- array initialisation used to
be non-standard, but is standard now, assuming I understand correctly
http://en.cppreference.com/w/cpp/language/zero_initialization .

Reviewed-by: Brian Paul <3cb4e1df5ec4da2c7c4af7c52cec8cf340a55a10@vmware.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler