bdw-gc: use 7.2alpha6 by default

7.1 is over two years old, and upstream recommends using 7.2alpha6
instead. This fixes build and test issues that 7.1 had on some systems,
and incompatibilities with some software.

Closes Homebrew/homebrew#8609.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>

Formula/bdw-gc.rb

@@ -1,33 +1,17 @@
 require 'formula'
 
 class BdwGc < Formula
+  # upstream recommends using 7.2alpha6 over 7.1
   homepage 'http://www.hpl.hp.com/personal/Hans_Boehm/gc/'
+  url 'http://www.hpl.hp.com/personal/Hans_Boehm/gc/gc_source/gc-7.2alpha6.tar.gz'
+  md5 '319d0b18cc4eb735c8038ece9df055e4'
+  version '7.2alpha6'
 
-  url 'http://www.hpl.hp.com/personal/Hans_Boehm/gc/gc_source/gc-7.1.tar.gz'
-  md5 '2ff9924c7249ef7f736ecfe6f08f3f9b'
-
-  devel do
-    url 'http://www.hpl.hp.com/personal/Hans_Boehm/gc/gc_source/gc-7.2alpha6.tar.gz'
-    md5 '319d0b18cc4eb735c8038ece9df055e4'
-    version '7.2alpha6'
-  end
-
-  # patch to fix inline asm errors with LLVM, present in upstream SVN
-  # some directory restructuring between 7.1 and 7.2a6 force us to have two
-  # versions of the same patch
   def patches
-    if ARGV.build_devel?
-      DATA
-    else
-      { :p0 => "https://trac.macports.org/export/86621/trunk/dports/devel/boehmgc/files/asm.patch" }
-    end
+    DATA # fix inline asm errors with LLVM, present in upstream SVN
   end
 
   def install
-    # ucontext has been deprecated in 10.6
-    # use this flag to force the header to compile
-    ENV.append 'CPPFLAGS', "-D_XOPEN_SOURCE" if MacOS.snow_leopard?
-
     system "./configure", "--disable-debug",
                           "--disable-dependency-tracking",
                           "--prefix=#{prefix}",