- Update build instructions in packages/DOS/README
- Extend 'VPATH' with 'vquic' and 'vssh'.
- Allow 'Makefile.dist' to build both 'lib' and 'src'.
- Allow using the Windows hosted djgpp cross compiler to build for MSDOS
under Windows.
- 'USE_SSL' -> 'USE_OPENSSL'
- Added a 'link_EXE' macro. Etc, etc.
- Linking 'curl.exe' needs '$(CURLX_CFILES)' too.
- Do not pick-up '../lib/djgpp/*.o' files. Recompile locally.
- Generate a gzipped 'tool_hugehelp.c' if 'USE_ZLIB=1'.
- Remove 'djgpp-clean'
- Adapt to new C-ares directory structure
- Use conditional variable assignments
Clarify the 'conditional variable assignment' in 'common.dj'.
Closes https://github.com/curl/curl/pull/6382
