diff --git a/Common-build-problems.md b/Common-build-problems.md
index e9b3332..9c115fc 100644
--- a/Common-build-problems.md
+++ b/Common-build-problems.md
@@ -94,7 +94,7 @@ pyenv versions
 ## Installing a 32 bit python on 64 bit Mac OS X (this will *not* work on Linux)
 
 ```sh
-CONFIGURE_OPTS="-with-arch=i386" CFLAGS="-arch i386" LDFLAGS="-arch i386" python-build options
+CONFIGURE_OPTS="--with-arch=i386" CFLAGS="-arch i386" LDFLAGS="-arch i386" python-build options
 ```
 
 ## Installing a system-wide Python