Investigate the space error seen with OON on GitHub!

[xparq]

If the NMAKE path in $(MAKE) contains spaces, this command failed, _until I removed the quotes from the supposedly unrelated DIR= clause!... :-o

rem ... !_make_! ... "DIR=!_dir_!" would FAIL if the NMAKE path has spaces! :-ooo
if exist %%i\*.%%x !_make_! /c compiling DIR=!_dir_! SRC_EXT_=%%x $(custom_build_options) || if errorlevel 1 exit -1

-> xparq/Out_of_Nothing#194, #5!

-> Also, I've seen it locally on a fresh Win10 test OON setup: the problem there was double-quoting $(MAKE)! (Fixed only there yet!) It seems NMAKE does it already for paths like "C:\Program Files"!