Add command "brew --env"

"brew --env" will set up a build environment and then dump certain ENV
variables (CC, CXX, LD, CFLAGS, CXXFLAGS, MAKEFLAGS).

If any of CC, CXX, LD are symlinks, now also output the target compiler.
(Typically these will be symlinks from eg /usr/bin/cc to /usr/bin/gcc-4.2).

This is a diagnostic command which may be merged into --config, turned
into an external command, or removed if it doesn't turn out to be useful.

1 files changed, 6 insertions, 0 deletions

diff --git a/bin/brew b/bin/brew
index bf8b06c99..ba2b622f3 100755
--- a/bin/brew
+++ b/bin/brew
@@ -94,6 +94,12 @@ begin
     end
   when '--config'
     dump_config
+  when '--env'
+    require 'hardware'
+    require 'extend/ENV'
+    ENV.extend(HomebrewEnvExtension)
+    ENV.setup_build_environment
+    dump_build_env ENV
 
     when 'home', 'homepage'
       if ARGV.named.empty?