Add a hack to force addition of -I/usr/include before any other include path discovered.

Index: buildtools/wafsamba/wscript
--- buildtools/wafsamba/wscript.orig
+++ buildtools/wafsamba/wscript
@@ -145,6 +145,11 @@ Currently the only tested value is 'smbtorture,smbd/sm
                    help=("Disable use of gettext"),
                    action="store_true", dest='disable_gettext', default=False)
 
+    opt.add_option('--with-dummy',
+                   help='dummy option to inject /usr/include',
+                   action='store', dest='libc_location', default='/usr',
+                   match = ['Checking for header sys/types.h'])
+
     gr = opt.option_group('developer options')
 
     gr.add_option('-C',