Restore missing REG_NOTBOL.

Reported by Victor <vico/tuta+io>.

src/sub.c

@@ -1,6 +1,6 @@
 /* sub.c: Substitution routines for the ed line editor.
  *
- *  Copyright © 1993-2022 Andrew L. Moore, SlewSys Research
+ *  Copyright © 1993-2024 Andrew L. Moore, SlewSys Research
  *
  *  This file is part of ed.
  */
@@ -460,6 +460,11 @@ substitute_matching (const regex_t *re, const ed_line_node_t *lp,
   int nil_prev;
   int nil_next = 1;
   int status;
+#ifdef REG_STARTEND
+  int eflag = REG_STARTEND;
+#else
+  int eflag = 0;
+#endif
 
   if (!(txt = get_buffer_line (lp, ed)))
     return ERR;
@@ -482,18 +487,14 @@ substitute_matching (const regex_t *re, const ed_line_node_t *lp,
   else if (!s_mod)
     s_mod = 1;
 
-#ifdef REG_STARTEND
-  for (*len = 0, eot = txt + lp->len, rm->rm_so = 0, rm->rm_eo = lp->len;
-       (!changed || (s_f & GSUB))
-         && !regexec (re, txt, SE_MAX, rm, REG_STARTEND);
-       txt += j, rm->rm_so = 0, rm->rm_eo = eot - txt)
-#else
+#ifndef REG_STARTEND
   if (ed->state->is_binary)
     NUL_TO_NEWLINE (txt, lp->len);
-  for (*len = 0, eot = txt + lp->len;
-       (!changed || (s_f & GSUB)) && !regexec (re, txt, SE_MAX, rm, 0);
-       txt += j)
-#endif  /* !REG_STARTEND */
+#endif
+  for (*len = 0, eot = txt + lp->len, rm->rm_so = 0, rm->rm_eo = lp->len;
+       (!changed || (s_f & GSUB))
+         && !regexec (re, txt, SE_MAX, rm, eflag);
+       txt += j, rm->rm_so = 0, rm->rm_eo = eot - txt, eflag |= REG_NOTBOL)
     {
       i = rm->rm_so, j = rm->rm_eo;
       nil_prev = nil_next, nil_next = !j;
@@ -583,18 +584,19 @@ count_matches (const regex_t *re, const char *txt, int len,
   int matched_prev = 0;
   int nul_prev;
   int nul_next = 1;
-
 #ifdef REG_STARTEND
-  for (eot = txt + len, rm->rm_so = 0, rm->rm_eo = len;
-       !regexec (re, txt, SE_MAX, rm, REG_STARTEND);
-       txt += off, rm->rm_so = 0, rm->rm_eo = eot - txt)
+  int eflag = REG_STARTEND;
 #else
+  int eflag = 0;
+#endif
+
+#ifndef REG_STARTEND
   if (buf->is_binary)
     NUL_TO_NEWLINE (txt, len);
-  for (eot = txt + len;
-       !regexec (re, txt, SE_MAX, rm, 0);
-       txt += off)
-#endif  /* !REG_STARTEND */
+#endif
+  for (eot = txt + len, rm->rm_so = 0, rm->rm_eo = len;
+       !regexec (re, txt, SE_MAX, rm, eflag);
+       txt += off, rm->rm_so = 0, rm->rm_eo = eot - txt, eflag |= REG_NOTBOL)
     {
       off = rm->rm_eo;
       nul_prev = nul_next;

testsuite/Makefile.am

@@ -60,7 +60,7 @@ ED_SCRIPTS_OK =								      \
 	a.t addr.t ascii.t bang1.t c1.t c2.t comment.t d.t delim.t	      \
 	e1.t e2.t e3.t e4.t e5.t g1.t g2.t g3.t g4.t g5.t i1.t i2.t	      \
 	j.t k.t m.t nl1.t nl2.t nl3.t nl4.t q2.t r1.t r2.t r3.t s1.t	      \
-	s2.t s3.t s4.t s5.t s6.t t1.t t2.t u.t v.t w.t
+	s2.t s3.t s4.t s5.t s6.t s7.t t1.t t2.t u.t v.t w.t
 
 # Ed scripts tested for expected standard output.
 ED_SCRIPTS_OK_SO =							      \

testsuite/s7.d

@@ -0,0 +1,5 @@
+  line 1
+ line 2
+line 3_5
+line 4
+line5

testsuite/s7.r

@@ -0,0 +1,5 @@
+_l!xine! 1
+_l!xine! 2
+_l!xine! 3_5!
+_l!xine! 4
+_l!xine!5

testsuite/s7.t

@@ -0,0 +1,5 @@
+g/./s/^[[:space:]]*/_/g\
+s/^_*/\
+/2\
+s/_*/x/2\
+s/8*/!/3g4