5457c871ef
if not defined (first run) these are now set blank but can be defined later.
the problem is that scons & cmake builds would link against different libraries since cmake added its own defaults.
now, by default, scons & cmake have the same libraries.
This fixes an obscure crash in MinGW where cmakes default linking with -ladvapi32 would crash on string formatting which used float precision as an argument, eg:
printf("%.*f", 3, value);
...without giving a useful backtrace or pointing to the line of code doing the string formatting.