Specify minimum version of Mac OS when building Python

Only applies if platform is mac.

component/python-2.7/buildout.cfg

@@ -44,6 +44,8 @@ configure-options =
   --with-system-expat
   --with-threads
 
+# Mac environment defines compatibility version if we are on a Mac OS system.
 environment =
+  MACOSX_DEPLOYMENT_TARGET=10.5
   CPPFLAGS=-I${zlib:location}/include -I${readline:location}/include -I${libexpat:location}/include -I${ncurses:location}/include -I${ncurses:location}/include/ncursesw -I${bzip2:location}/include  -I${gdbm:location}/include -I${openssl:location}/include -I${sqlite3:location}/include -I${gettext:location}/include
   LDFLAGS=-L${zlib:location}/lib -L${readline:location}/lib -L${libexpat:location}/lib -L${ncurses:location}/lib -L${bzip2:location}/lib -L${gdbm:location}/lib -L${openssl:location}/lib -L${sqlite3:location}/lib -Wl,-rpath,${zlib:location}/lib -Wl,-rpath,${readline:location}/lib -Wl,-rpath,${libexpat:location}/lib -Wl,-rpath,${ncurses:location}/lib -Wl,-rpath,${bzip2:location}/lib -Wl,-rpath,${gdbm:location}/lib -Wl,-rpath,${openssl:location}/lib -Wl,-rpath,${sqlite3:location}/lib -L${gettext:location}/lib -Wl,-rpath,${gettext:location}/lib