[PATCH] Fix build failure with Perl 5.36

[Brendan O'Dea]

Fix a build failure for Perl 5.36 caused by a namespace conflict of
the symbol `regexp' (http://bugs.debian.org/1014289).

diff --git a/perl.xs b/perl.xs
index 86c04e3..ee658d2 100644
--- a/perl.xs
+++ b/perl.xs
@@ -118,20 +118,20 @@
 
 /* for vile */
 #define MARK vile_MARK
+#define regexp vile_regexp
 #include "estruct.h"
 #include "edef.h"
 #include "api.h"
 #undef MARK
+#undef regexp
 #undef ABORT
 
 /* for perl */
 #define main perl_main
-#define regexp perl_regexp
 #include <EXTERN.h>
 #include <perl.h>
 #include <XSUB.h>
 #undef main
-#undef regexp
 #undef dofile
 
 #ifdef __GNUC__