CBMC does not build using CMake & MSVC

[karkhaz]

The issue is with src/ansi-c/library-check.sh. There are (at least) two issues:

• MSVC doesn't understand the flags passed to $CC. It thinks that -Werror is an argument to -Wall. Don't ask.
• The $CC variables should be quoted in that script, in case the path to the compiler contains spaces. Otherwise the shell tries to run a compiler called C:\Program.

Fix on the way shortly.

[karkhaz]

Oh, and this is using the VisualStudio developer console. No cygwin or mingw.