uCON64 Code (SVN)

- Handle sign bit extension that AFAIK would normally not occur with a proper
implementation of stat(). It does occur with for example MinGW and MinGW-w64
(without -D_FILE_OFFSET_BITS=64) of which stat() fills struct stat.st_size
with values up to 4GB-1. Since stat.st_size is signed, values over 2GB-1 are
"actually" negative. stat() of 32-bit GNU/Linux (without
-D_FILE_OFFSET_BITS=64) just fails for those files. However, for MinGW and
MinGW-w64 uCON64 uses _stati64().

- Just use a comma everywhere.

- Fixed oversight in fix to ioapi.h. It does not invalidate any of the
previously mentioned platform tests, because _FILE_OFFSET_BITS is defined
afterwards (to be 64) in either case.

- Changes to make unzip 1.1 work for all supported platforms. Tested with:
+ GNU/Linux x86_64 GCC 4.8.5
+ DJGPP GCC 5.3.0
+ MinGW GCC 6.3.0
+ MinGW-w64 GCC 10.3.0 (also checked with -fanalyzer)
+ MinGW-w64 Clang 12.0.1 (also checked with --analyze)
+ 32-bit Cygwin GCC 11.2.0
+ 64-bit Cygwin GCC 11.2.0 (also checked with -fanalyzer)
+ Visual C++ 2015 (also checked with /analyze)
+ Visual C++ 2019 (also checked with /analyze)
+ macOS M1 Clang 12.0.5
+ GNU/Linux　ARMv7 GCC 8.3.0
- Added support for large file API of zlib and unzip.
- Fixed crash when running uCON64 on ZIP file that is password protected.

- Upgraded to unzip 1.1 (original files).

- Fixed signed/unsigned mismatch.

- Added support for uploading ROM images without a header to gd.c. --xgd3 and
--xgd6 still require files to have a header to avoid confusion.
- Removed some redundant code (gd3_send_bytes() and gd6_send_bytes() call
ucon64_gauge() themselves).

- Fixed some issues in MinGW, MinGW-w64 and Visual C++ ports that made them
choke on files larger than 2 GB. On 32-bit UNIX adding
-D_FILE_OFFSET_BITS=64 to CFLAGS has a similar effect. The MinGW port has
been successfully tested on Windows 98 by Mystic_Merlin.
- Previous change modified the dependencies, so the makefiles have been
updated.
- Reduced scope of variables in ucon64_dat.c. These were apparently all missed
by Cppcheck.

- MinGW has lost its website (www.mingw.org). Updated URL in FAQ.
- Updated answer to FAQ question 55 by referring to ROM (memory unit) dumping.
- Fixed error when dynamically linking to libdiscmage on an unsupported
platform ;-)

- Fixed zero-length allocation issue indicated by --analyze of Clang 12.0.0.