* src/include/nonposix.h (write, dup, dup2, close) [_MSC_VER]:

* src/include/nonposix.h (write, dup, dup2, close) [_MSC_VER]:
New macros.

* src/roff/groff/pipeline.c: Declare strcasecmp.
(run_pipeline) [_WIN32]: Use function name variants which don't
start with `_'.
Fix stream handling.

* src/include/nonposix.h: Fix declaration of `system_shell_name'.
Declare `spawnvp_wrapper' and macro definitions of spawnvp only
for platforms which use the native Win32 runtime libraries.
(FLUSH_INPUT_PIPE) [_UWIN]: Provide non-empty version.

* src/libs/libgroff/quotearg.c (QUOTE_ARG_MALLOC_ERROR,
QUOTE_ARG_REALLOC_ERROR): Fix string.

* src/preproc/html/pre-html.cpp: Remove declaration of
`spawnvp_wrapper'.
Don't use __MINGW32__.
s/DEBUG_FILE/DEBUG_FILE_DIR/.
(DEBUG_TEXT, DEBUG_NAME, DEBUG_FILE) [DEBUGGING]: New macros.
(OUTPUT_STREAM, PS_OUTPUT_STREAM, REGION_OUTPUT_STREAM): New macros.
(char_buffer::run_output_filter) [MAY_FORK_CHILD_PROCESS]: Fix
calls to `set_redirection' and `WAIT'.
[MAY_SPAWN_ASYNCHRONOUS_CHILD]: Remove unused variable `i' and `j'.
Fix calls to `set_redirection' and `save_and_redirect'.
(char_buffer::do_html, char_buffer::do_image) [DEBUGGING]: Fix calls
to `set_redirection' and `save_and_redirect'.
(usage): Fix message.
(makeTempFiles, main): Use `DEBUG_FILE'.