Steph is a portable C library for text mode windows, menus, dialogs, etc. The interface with the underlying system is provided by a separate library, so to port to a new system, only the interface library needs to be rewritten. Interface libraries are provided for Unix/Curses and IBM PC compatibles running DOS.
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.
4tH is a Forth compiler with a little difference. Instead of the standard Forth engine it features a conventional compiler. 4tH is a very small compiler that can create bytecode, C-embeddable bytecode, standalone executables, but also works fine as a scripting language. It supports about 95% of the ANS Forth CORE wordset and features conditional compilation, pipes, files, assertions, forward declarations, enumerations, structures, suspended execution, recursion, include files, etc. It comes with an RPN calculator, line editor, preprocessor, compiler, decompiler, C-source generator, a virtual machine, and a multitasking environment.
Yasm is a complete rewrite of the NASM assembler. It currently supports the x86 and AMD64 instruction sets, accepts NASM and GAS assembler syntaxes, outputs binary, ELF32, ELF64, COFF, Mach-O (32 and 64), RDOFF2, Win32, and Win64 object formats, and generates source debugging information in STABS, DWARF 2, and CodeView 8 formats.