Set LD to CC

This is generally the right thing to do. It should fix more build problems than it hinders. Especially on Snow Leopard.

This fixes the pngcrush build.

Library/Homebrew/brewkit.rb

@@ -48,6 +48,11 @@ else
   ENV['CXX']="g++-4.2"
   cflags = ['-O3']
 end
+# in rare cases this may break your builds, as the tool for some reason wants
+# to use a specific linker, however doing this in general causes formula to
+# build more successfully because we are changing CC and many build systems
+# don't react properly to that
+ENV['LD']=ENV['CC']
 
 # optimise all the way to eleven, references:
 # http://en.gentoo-wiki.com/wiki/Safe_Cflags/Intel
@@ -106,9 +111,11 @@ module HomebrewEnvExtension
     when 10.5
       self['CC']=nil
       self['CXX']=nil
+      self['LD']=nil
     when 10.6..11.0
       self['CC']='gcc-4.0'
       self['CXX']='g++-4.0'
+      self['LD']=self['CC']
       remove_from_cflags '-march=core2'
       self.O3
     end
@@ -124,6 +131,7 @@ module HomebrewEnvExtension
     # Sometimes you want to downgrade from LLVM to GCC 4.2
     self['CC']="gcc-4.2"
     self['CXX']="g++-4.2"
+    self['LD']=self['CC']
     self.O3
   end
   def osx_10_4