ENV: protect against RUBYLIB/RUBYOPT

Some things can break in hard to debug ways if users or build scripts
set these variables, causing our otherwise quite robust Ruby wrappers
to fail. In theory, we could also use `--disable-rubyopt`, but this is
not supported in Ruby 1.8 (and we still care about it).

Library/ENV/4.3/cc

@@ -1,5 +1,7 @@
 #!/bin/sh
 # Make sure this shim uses the same Ruby interpreter that is used by Homebrew.
+unset RUBYLIB
+unset RUBYOPT
 exec "$HOMEBREW_RUBY_PATH" -x "$0" "$@"
 #!/usr/bin/env ruby -W0
 

Library/ENV/scm/git

@@ -1,5 +1,7 @@
 #!/bin/sh
 # Make sure this shim uses the same Ruby interpreter that is used by Homebrew.
+unset RUBYLIB
+unset RUBYOPT
 exec "$HOMEBREW_RUBY_PATH" -x "$0" "$@"
 #!/usr/bin/env ruby -W0