Update bare GNU Make `Makefile.m32` to:
- Move objects into a subdirectory.
- Add support for MS-DOS. Tested with DJGPP.
- Add support for Watt-32 (on MS-DOS).
- Add support for AmigaOS.
- Rename `Makefile.m32` to `Makefile.mk`
- Replace `ARCH` with `TRIPLET`.
- Build `tool_hugehelp.c` proper (when tools are available).
- Drop MS-DOS compatibility macro `USE_ZLIB` (replaced by `HAVE_LIBZ`)
- Add support for `ZLIB_LIBS` to override `-lz`.
- Omit object files when building examples.
- Default `CC` to `gcc` once again, for convenience. (Caveat: compiler
name `cc` cannot be set now.)
- Set `-DCURL_NO_OLDIES` for examples, like autotools does.
- Delete `makefile.dj` files. Notice the configuration details and
defaults are not retained with the new method.
- Delete `makefile.amiga` files. A successful build needs a few custom
options. We're also not retaining all build details from the existing
Amiga make files.
- Rename `Makefile.m32` to `Makefile.mk` to reflect that they are not
Windows/MinGW32-specific anymore.
- Add support for new `CFG` options: `-map`, `-debug`, `-trackmem`
- Set `-DNDEBUG` by default.
- Allow using `-DOS=...` in all `lib/config-*.h` headers, syncing this
with `config-win32.h`.
- Look for zlib parts in `ZLIB_PATH/include` and `ZLIB_PATH/lib`
instead of bare `ZLIB_PATH`.
Note that existing build configurations for MS-DOS and AmigaOS likely
become incompatible with this change.
Example AmigaOS configuration:
```
export CROSSPREFIX=/opt/amiga/bin/m68k-amigaos-
export CC=gcc
export CPPFLAGS='-DHAVE_PROTO_BSDSOCKET_H'
export CFLAGS='-mcrt=clib2'
export LDFLAGS="${CFLAGS}"
export LIBS='-lnet -lm'
make -C lib -f Makefile.mk
make -C src -f Makefile.mk
```
Example MS-DOS configuration:
```
export CROSSPREFIX=/opt/djgpp/bin/i586-pc-msdosdjgpp-
export WATT_PATH=/opt/djgpp/net/watt
export ZLIB_PATH=/opt/djgpp
export OPENSSL_PATH=/opt/djgpp
export OPENSSL_LIBS='-lssl -lcrypt'
export CFG=-zlib-ssl
make -C lib -f Makefile.mk
make -C src -f Makefile.mk
```
Closes#9764
This spellchecker checks markdown files. For this reason this job
converts all man pages in the repository to markdown with pandoc before
the check runs.
The perl script 'cleanspell' filters out details from the man page in
the process, to avoid the spellchecker trying to spellcheck things it
can't. Like curl specific symbols and the SYNOPSIS and EXAMPLE sections
of libcurl man pages.
The spell checker does not check words in sections that are within pre,
strong and em tags.
'spellcheck.words' is a custom word list with additional accepted words.
Closes#9523
