Allegro is a multi-platform game library for C/C++ developers that provides many functions for graphics, sounds, player input (keyboard, mouse, and joystick), and timers. It also provides fixed and floating point mathematical functions, 3D functions, file management functions, compressed datafile, and a GUI.
Mercat is a light-weight, cross platform programming language. It is garbage collected and self hosting and produces portable byte-compiled binaries that can be executed on any platform with the appropriate interpreter. Interpreters are available for Linux, DOS (32-bit) and DOS (16-bit) and the interpreter source should be easily compilable for other platforms.
tal aligns common characters at the ends of lines. This is especially useful for making long C macro definitions look nice or for repairing "broken" comment boxes. tal works on any kind of common ending, which it autodetects. Intended as, but not limited to being, a filter program ("plug-in") for text editors.
An almost ISO C compatible C compiler that produces binaries for 6502-based computers. Targets that are supported out of the box are: Apple ][, Atari 8-bit machines, Commodore C64/C128/C16/C116, Commodore Plus/4, Commodore 600/700, GEOS for C64, and Lynx. The package includes a complete suite of assembler development tools (assembler, linker, archiver) which allows mixing of C and assembler code.
reversible hexdump is a hexdump/hex2bin-toolkit that dumps to a special readable and reversible hexadecimal byte-dump, where you can not only change bytes, but also insert or delete bytes. It has a flush-switch, where it will output hexbytes for each single char it reads. This is especially useful (imho) for watching output from slow devices (e.g., serial devices like mice). The hex2bin-utility (the reverse-hexdump) not only accepts hexbytes for input, but also double-quoted strings with most of the escape-chars known from C and makes good attempts at undumping even hexdumps with repetition-lines (a "*" on its own line). It's written in ANSI C.