Compile and link. Default: -64 if running on 64-bit platform, otherwise -32
Generate code for a 32-bit or 64-bit environment. The -32 option sets int, long and pointer to 32 bits and generates code that runs on any i386 system. The -64 option sets int to 32 bits and long and pointer to 64 bits and generates code for AMD’s x86-64 architecture.