Restore ability to inherit compiler from environmental variables: chapmanb/bcbio-nextgen#424
Restore ability to inherit compiler from environmental variables: chapmanb/bcbio-nextgen#424

Linuxbrew/brew,rwhogg/brew,Linuxbrew/brew,maxim-belkin/brew,maxim-belkin/brew,hanxue/linuxbrew,hanxue/linuxbrew,rwhogg/brew,Linuxbrew/brew,hanxue/linuxbrew,Linuxbrew/brew,rwhogg/brew,maxim-belkin/brew