一个完整的C编译器源代码，
可以编译出windows下可执行的exe文件，程序不大，总共不到2w行代码，是学习C编译器的好例子。
Features

　　* SMALL! You can compile and execute C code everywhere, for example on rescue disks (about 100KB for x86 TCC executable, including C preprocessor, C compiler, assembler and linker).
　　* FAST! tcc generates x86 code. No byte code overhead. Compile, assemble and link several times faster than GCC.
　　* UNLIMITED! Any C dynamic library can be used directly. TCC is heading torward full ISOC99 compliance. TCC can of course compile itself.
　　* SAFE! tcc includes an optional memory and bound checker. Bound checked code can be mixed freely with standard code.
　　* Compile and execute C source directly. No linking or assembly necessary. Full C preprocessor and GNU-like assembler included.
　　* C scr ipt supported : just add '#!/usr/local/bin/tcc -run' at the first line of your C source, and execute it directly from the command line.
　　* With libtcc, you can use TCC as a backend for dynamic code generation.