Mac下更新gcc版本

localhost:hello chenzhen$ port search gcc
  apple-gcc40 @5494 (lang)
      Apple's version of gcc 4.0
  
  apple-gcc42 @5666.3_14 (lang)
      Apple's version of gcc 4.2
  
  arm-aout-gcc @3.3.6 (cross, devel)
      gcc cross-compilers for arm-aout, with newlib runtime library.
  
  arm-elf-gcc @4.7.3 (cross, devel)
      gcc cross-compilers for arm-elf, with newlib runtime library.
  
  arm-elf-gcc3 @3.4.6_2 (cross, devel)
      gcc 3.x cross-compilers for arm-elf, with newlib runtime library.
  
  arm-none-eabi-gcc @4.7.3_1 (cross, devel)
      The GNU compiler collection for arm-none-eabi
  
  arm-none-linux-gnueabi-gcc @2005q3-2 (cross, devel)
      gcc 3.x cross-compilers for arm-none-linux-gnueabi.
  
  arm-rtems-gcc @4.2.3 (cross, devel)
      gcc cross-compilers for arm-rtems, with newlib runtime library.
  
  avr-gcc @4.9.1 (cross, devel)
      The GNU compiler collection for avr

localhost:hello chenzhen$ sudo port install gcc44

localhost:hello chenzhen$ port select --list gcc
  Available versions for gcc:
    apple-gcc42
    llvm-gcc42
    mp-gcc44 (active)
    mp-gcc48
    none

localhost:hello chenzhen$ sudo port select --set gcc mp-gcc44