Update GCC 4.9 to snapshot at 20130505
Update GCC 4.9 to snapshot at 20130505

* Configure options improvements.
  - Enable checking as release.
  - Enable libstdc++ time.

UniqMartin/homebrew-versions,Ashton-W/homebrew-versions,coeligena/homebrew-verscustomized,DomT4/homebrew-versions,jimhe/homebrew-versions,heuermh/homebrew-versions