More fixes for MSVC compiler.
* doc/Makefile.sub, contrib/mom/Makefile.sub (GROFF_BIN_PATH): Use
$(SEP).
* src/include/nonposix.h (STDIN_FILENO, STDOUT_FILENO,
STDERR_FILENO) [_MSC_VER]: Define conditionally.
(getpid) [_MSC_VER]: Remove.
Include direct.h and process.h conditionally.
* src/roff/troff/node.cpp (suppress_node::tprint): Don't use
parentheses for a_delete.
* src/utils/lookbib/lookbib.cpp: Include nonposix.h.
* test-groff: Replaced with...
* test-groff.in: This new template to handle path separator
properly.
* configure.ac: Check for direct.h and process.h.
Generate test-groff script.
* configure, src/include/config.hin: Regenerated.