typespeed: Fix hardcoded gcc

Typespeed-0.6.5 stopped development in 2008 but hard-codes `gcc`
into two of their Makefiles.  Use `ENV.cc` instead.  Tested on
Lion with clang and llvm-gcc.  Typespeed also does a `chgrp games`
Even though that group will likely not exist, the software still
works without error because the owner is correct, and the `chgrp`
does not stop the build if it is unsuccessful.

Closes Homebrew#11848.

Signed-off-by: Jack Nagel <[email protected]>

Library/Formula/typespeed.rb

@@ -6,7 +6,10 @@ class Typespeed < Formula
   md5 '578102b418c7df84903d3e90df2e7483'
 
   def install
-    system "./configure", "--prefix=#{prefix}", "--disable-debug", "--disable-dependency-tracking"
+    # Fix the hardcoded gcc.
+    inreplace 'src/Makefile.in', 'gcc', "#{ENV.cc}"
+    inreplace 'testsuite/Makefile.in', 'gcc', "#{ENV.cc}"
+    system "./configure", "--prefix=#{prefix}", "--disable-dependency-tracking"
     system "make install"
   end
 end