diff --git a/Formula/gmp.rb b/Formula/gmp.rb
index ee0cba141f..6360fe96f2 100644
--- a/Formula/gmp.rb
+++ b/Formula/gmp.rb
@@ -27,7 +27,7 @@ class Gmp < Formula
       args << "--build=x86_64-apple-darwin"
     else
       ENV.m32
-      args << "--host=none-apple-darwin"
+      args << "--build=none-apple-darwin"
     end
 
     system "./configure", *args
diff --git a/Formula/mpfr.rb b/Formula/mpfr.rb
index 80aec07b8b..a8733d1fd9 100644
--- a/Formula/mpfr.rb
+++ b/Formula/mpfr.rb
@@ -25,7 +25,7 @@ class Mpfr < Formula
       args << "--build=x86_64-apple-darwin"
     else
       ENV.m32
-      args << "--host=none-apple-darwin"
+      args << "--build=none-apple-darwin"
     end
 
     system "./configure", *args