diff --git a/Formula/ghc.rb b/Formula/ghc.rb
index 330735ea078..6b49abf2a40 100644
--- a/Formula/ghc.rb
+++ b/Formula/ghc.rb
@@ -84,6 +84,7 @@ class Ghc < Formula
       if Hardware.is_64_bit? and not build.build_32_bit?
         arch = 'x86_64'
       else
+        ENV.m32 # Need to force this to fix build error on internal libgmp.
         arch = 'i386'
       end