Correctly check for no-makefile compile

Under Windows with MSVC we use the IDE to compile,
in this case we infer some compiler flags usually
set by Makefile.

The condition to check this was wrong, namely when compiling
with mingw under Windows 64 bit we always set IS_64BIT and
USE_BSFQ even if compiled with ARCH=x86-32 (this is how I
found it).

Small code style touches while there.

No functional change.