make_ext.pl: fix regenerate makefile failed while $cc changed

While $cc changed, the existance of 'xdefine' caused makefile
regeneration failed.

Upstream-Status: Pending

Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
---
 make_ext.pl | 4 ++++
 1 file changed, 4 insertions(+)

Index: perl-5.24.1/make_ext.pl
===================================================================
--- perl-5.24.1.orig/make_ext.pl
+++ perl-5.24.1/make_ext.pl
@@ -335,6 +335,10 @@ sub build_extension {
                 print "Deleting non-Cross makefile\n";
                 close $mfh or die "close $makefile: $!";
                 _unlink($makefile);
+                if(-e 'xdefine') {
+                    print "Deleting xdefine for regenerate makefile\n";
+                    _unlink('xdefine');
+                }
             }
         }
     } else {