(*ACCEPT) at start of branch was not recording "may match empty string".

ChangeLog

@@ -111,6 +111,9 @@ within it, the nested lookbehind was not correctly processed. For example, if
     (c) An empty string partial hard match can be returned for \z and \Z as it
     is documented that they shouldn't match. 
     
+22. A branch that started with (*ACCEPT) was not being recognized as one that
+could match an empty string. 
+
 
 Version 10.33 16-April-2019
 ---------------------------

src/pcre2_compile.c

@@ -5302,6 +5302,7 @@ PCRE2_UCHAR *tempcode;
 PCRE2_UCHAR *previous = NULL;
 PCRE2_UCHAR op_previous;
 BOOL groupsetfirstcu = FALSE;
+BOOL had_accept = FALSE;
 BOOL matched_char = FALSE;
 BOOL previous_matched_char = FALSE;
 const uint8_t *cbits = cb->cbits;
@@ -5436,7 +5437,7 @@ for (;; pptr++)
   if (meta < META_ASTERISK || meta > META_MINMAX_QUERY)
     {
     previous = code;
-    if (matched_char) okreturn = 1;
+    if (matched_char && !had_accept) okreturn = 1;
     }
 
   previous_matched_char = matched_char;
@@ -6075,7 +6076,7 @@ for (;; pptr++)
     workspace overflow. Do not set firstcu after *ACCEPT. */
 
     case META_ACCEPT:
-    cb->had_accept = TRUE;
+    cb->had_accept = had_accept = TRUE;
     for (oc = cb->open_caps;
          oc != NULL && oc->assert_depth >= cb->assert_depth;
          oc = oc->next)

testdata/testoutput2

@@ -11241,6 +11241,7 @@ No match
 
 /(*ACCEPT)a/I,aftertext
 Capture group count = 0
+May match empty string
 Subject length lower bound = 0
     bax
  0: 
@@ -16911,6 +16912,7 @@ Subject length lower bound = 3
 
 /(*ACCEPT:XX)^abc/I
 Capture group count = 0
+May match empty string
 Subject length lower bound = 0
 
 /abc/replace=xyz