patch 8.1.0102: cannot build without syntax highlighting

Problem:    Cannot build without syntax highlighting.
Solution:   Add #ifdef around using reg_do_extmatch.

src/regexp.c

@@ -8376,11 +8376,15 @@ vim_regexec_multi(
 #ifdef FEAT_EVAL
 	    report_re_switch(pat);
 #endif
+#ifdef FEAT_SYN_HL
 	    // checking for \z misuse was already done when compiling for NFA,
 	    // allow all here
 	    reg_do_extmatch = REX_ALL;
+#endif
 	    rmp->regprog = vim_regcomp(pat, re_flags);
+#ifdef FEAT_SYN_HL
 	    reg_do_extmatch = 0;
+#endif
 
 	    if (rmp->regprog != NULL)
 		result = rmp->regprog->engine->regexec_multi(

src/version.c

@@ -761,6 +761,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    102,
 /**/
     101,
 /**/