glibc: Symlink /etc/localtime for Linuxbrew
glibc: Symlink /etc/localtime for Linuxbrew

Set the local time zone.

Closes #Homebrew/linuxbrew#390

Linuxbrew/homebrew-core,forevergenin/homebrew-core,LinuxbrewTestBot/homebrew-core,maxim-belkin/homebrew-core,rwhogg/homebrew-core,LinuxbrewTestBot/homebrew-core,forevergenin/homebrew-core,rwhogg/homebrew-core,maxim-belkin/homebrew-core,Linuxbrew/homebrew-core