Refactor \X regex handling to avoid a typical case table lookup

Prior to this commit 98.4% of Unicode code points that went through \X
had to be looked up to see if they begin a grapheme cluster; then looked
up again to find that they didn't require special handling.  This commit
refactors things so only one look-up is required for those 98.4%.  It
changes the table generated by mktables to accomplish this, and hence
the name of it, and references to it are changed to correspond.

1 files changed, 3 insertions, 3 deletions

diff --git a/utf8.c b/utf8.c
index 4ba29d859b..dd103cd4ad 100644
--- a/utf8.c
+++ b/utf8.c
@@ -2210,13 +2210,13 @@ Perl_is_utf8_mark(pTHX_ const U8 *p)
 }
 
 bool
-Perl_is_utf8_X_begin(pTHX_ const U8 *p)
+Perl_is_utf8_X_regular_begin(pTHX_ const U8 *p)
 {
     dVAR;
 
-    PERL_ARGS_ASSERT_IS_UTF8_X_BEGIN;
+    PERL_ARGS_ASSERT_IS_UTF8_X_REGULAR_BEGIN;
 
-    return is_utf8_common(p, &PL_utf8_X_begin, "_X_Begin");
+    return is_utf8_common(p, &PL_utf8_X_regular_begin, "_X_Regular_Begin");
 }
 
 bool