superenv: Remove HOMEBREW_PREFIX/bin from PATH

We add the bins from all deps instead. Rationale: formula find and use eg. GNU-coreutils versions of things and then break. Only allow formula to use tools that they depend on and expect.

I want to go further and only add include paths etc. for dependencies, I have done some work on this, but I fear it may be impossible. If an include path is eg. /usr/local/lib/foo/include, is it possible to know if this path is bad? Not always AFAICT.

Library/Homebrew/build.rb

@@ -97,6 +97,7 @@ def install f
 
   if superenv?
     ENV.deps = keg_only_deps.map(&:to_s)
+    ENV.all_deps = f.recursive_deps.map(&:to_s)
     ENV.x11 = f.recursive_requirements.detect{|rq| rq.class == X11Dependency }
     ENV.setup_build_environment
     f.recursive_requirements.each { |rq| rq.modify_build_environment }

Library/Homebrew/cmd/sh.rb

@@ -8,6 +8,10 @@ module Homebrew extend self
       ENV.deps = Formula.installed.select{|f| f.keg_only? and f.opt_prefix.directory? }.map(&:name)
     end
     ENV.setup_build_environment
+    if superenv?
+      # superenv stopped adding brew's bin but generally user's will want it
+      ENV['PATH'] = ENV['PATH'].split(':').insert(1, "#{HOMEBREW_PREFIX}/bin").join(':')
+    end
     ENV['PS1'] = 'brew \[\033[1;32m\]\w\[\033[0m\]$ '
     ENV['VERBOSE'] = '1'
     ENV['HOMEBREW_LOG'] = '1'

Library/Homebrew/superenv.rb

@@ -23,6 +23,7 @@ end
 
 class << ENV
   attr :deps, true
+  attr :all_deps, true # above is just keg-only-deps
   attr :x11, true
   alias_method :x11?, :x11
 
@@ -104,8 +105,7 @@ class << ENV
       paths << "#{MacSystem.xcode43_developer_dir}/usr/bin"
       paths << "#{MacSystem.xcode43_developer_dir}/Toolchains/XcodeDefault.xctoolchain/usr/bin"
     end
-    paths += deps.map{|dep| "#{HOMEBREW_PREFIX}/opt/#{dep}/bin" }
-    paths << HOMEBREW_PREFIX/:bin
+    paths += all_deps.map{|dep| "#{HOMEBREW_PREFIX}/opt/#{dep}/bin" }
     paths << "#{MacSystem.x11_prefix}/bin" if x11?
     paths += %w{/usr/bin /bin /usr/sbin /sbin}
     paths.to_path_s
@@ -256,6 +256,7 @@ if not superenv?
   ENV.prepend 'PATH', "#{HOMEBREW_PREFIX}/bin", ':' unless ORIGINAL_PATHS.include? HOMEBREW_PREFIX/'bin'
 else
   ENV.deps = []
+  ENV.all_deps = []
 end