discount: fix ./configure under clang

Also reported upstream.

Formula/discount.rb

@@ -3,7 +3,13 @@ require 'formula'
 class Discount < Formula
   homepage 'http://www.pell.portland.or.us/~orc/Code/discount/'
   url 'https://github.com/Orc/discount/tarball/v2.1.3'
-  md5 '0c6db0556506724dac050ec19ab625b5'
+  sha1 '9d2dc33a1f80e7dd56f2c7ee1aec0a3e6e60302f'
+
+  # Work around clang-incompatible test
+  # We know we have strcasecmp and strncasecmp, so just
+  # skip the test. Repoted upstream in
+  # https://github.com/Orc/discount/issues/55
+  def patches; DATA; end
 
   def install
     system "./configure.sh", "--prefix=#{prefix}",
@@ -16,3 +22,32 @@ class Discount < Formula
     system "make install.everything"
   end
 end
+
+__END__
+diff --git a/configure.sh b/configure.sh
+index 43ef971..821832b 100755
+--- a/configure.sh
++++ b/configure.sh
+@@ -102,22 +102,6 @@ else
+     AC_DEFINE 'COINTOSS()' '1'
+ fi
+ 
+-if AC_CHECK_FUNCS strcasecmp; then
+-    :
+-elif AC_CHECK_FUNCS stricmp; then
+-    AC_DEFINE strcasecmp stricmp
+-else
+-    AC_FAIL "$TARGET requires either strcasecmp() or stricmp()"
+-fi
+-
+-if AC_CHECK_FUNCS strncasecmp; then
+-    :
+-elif AC_CHECK_FUNCS strnicmp; then
+-    AC_DEFINE strncasecmp strnicmp
+-else
+-    AC_FAIL "$TARGET requires either strncasecmp() or strnicmp()"
+-fi
+-
+ if AC_CHECK_FUNCS fchdir || AC_CHECK_FUNCS getcwd ; then
+     AC_SUB 'THEME' ''
+ else