Since GNU make and MSVC nmake need special rules for compiling this module that
causes failure with the other 'make' variant, the configure script needs to
comment out incompatible rules. Using symbols GNU_MAKE_ONLY and NMAKE_ONLY to
enable only one of the rulesets only.
Since one of the MSVC nmake rules uses curly brackets the shortcut script
.conf.win64-vcpp needs to be modified to exclude cpu/softfloat3e/Makefile
from removal of these usually unwanted characters.