SharpMuPDF/mupdf/thirdparty/curl/packages/DOS

Gisle Vanem made curl build fine on DOS (and MingW) with djgpp, OpenSSL and his
Watt-32 stack.

'make djgpp' in the root curl dir should build it fine.

Note 1: djgpp 2.04 beta has a sscanf() bug so the URL parsing isn't
done properly. Use djgpp 2.03 until they fix it.

Note 2: Compile Watt-32 (and OpenSSL) with the same version of djgpp.
Otherwise things go wrong because things like FS-extensions and
errnos have been changed between releases.