Be more consistent in the use of path separators.
Add a second version of Makefile variables that contain paths,
one with a trailing separator, and one without (prefixed with R_
for use in Makefile rules).
Also, in dat/luahelper,
Updates due to correspond to the Makefile.nmake changes.
Add Makefile variable AWK to use $(AWK) instead of hardcoded awk.
f12d755ba2