llvm: strip binary files & fix style
llvm: strip binary files & fix style

1. Fix style for "glibc" dependency
2. Remove `if OS.linux?` for "binutils" dependency
  (Because it is within `unless OS.mac?`)
3. Strip executables, libraries, and object files to reduce their size

Closes Linuxbrew/homebrew-core#3163.

Signed-off-by: Maxim Belkin <032baa6ccf1d4eaa4536fc4f9b83b9a1f593449a@gmail.com>

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