* Makefile.in (SEP): Replaced with...

* Makefile.in (SEP): Replaced with...
(RT_SEP, SH_SEP): Separators for the target platform's native path
separator and the build environment, respectively.
(fontpath, tmacpath): Use RT_SEP.
(MDEFINES): Updated.

* contrib/mom/Makefile.sub (GROFF_BIN_PATH): Use SH_SEP.
* doc/Makefile.sub (GROFF_BIN_PATH): Use SH_SEP.
* src/preproc/eqn/Makefile.sub (neqn): Use SH_SEP.
* src/roff/nroff/Makefile.sub (nroff): Use SH_SEP.

* fonts/devlj4/Makefile.sub (LJ4RES): Set to 1200.  This helps to
reduce alignment problems with newer printers which use built-in
TrueType fonts (instead of the older Intellifonts).  The ideal
solution is to provide a second set of groff metric files, but this
is extremely time-consuming to produce, given that HP's metric
files are very rudimentary.