awk: fix compat issue found by gpm build

function                                             old     new   delta
as_regex                                             105     131     +26
hash_find                                            247     233     -14
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/1 up/down: 26/-14)             Total: 12 bytes

2 files changed, 19 insertions, 3 deletions

diff --git a/editors/awk.c b/editors/awk.c
index 3f8368c..9b15b3c 100644
--- a/editors/awk.c
+++ b/editors/awk.c
@@ -604,8 +604,8 @@ static void *hash_find(xhash *hash, const char *name)
 			hash_rebuild(hash);
 
 		l = strlen(name) + 1;
-		hi = xzalloc(sizeof(hash_item) + l);
-		memcpy(hi->name, name, l);
+		hi = xzalloc(sizeof(*hi) + l);
+		strcpy(hi->name, name);
 
 		idx = hashidx(name) % hash->csize;
 		hi->next = hash->items[idx];
@@ -1482,6 +1482,7 @@ static node *mk_splitter(const char *s, tsplitter *spl)
  */
 static regex_t *as_regex(node *op, regex_t *preg)
 {
+	int cflags;
 	var *v;
 	const char *s;
 
@@ -1490,7 +1491,17 @@ static regex_t *as_regex(node *op, regex_t *preg)
 	}
 	v = nvalloc(1);
 	s = getvar_s(evaluate(op, v));
-	xregcomp(preg, s, icase ? REG_EXTENDED | REG_ICASE : REG_EXTENDED);
+
+	cflags = icase ? REG_EXTENDED | REG_ICASE : REG_EXTENDED;
+	/* Testcase where REG_EXTENDED fails (unpaired '{'):
+	 * echo Hi | awk 'gsub("@(samp|code|file)\{","");'
+	 * gawk 3.1.5 eats this. We revert to ~REG_EXTENDED
+	 * (maybe gsub is not supposed to use REG_EXTENDED?).
+	 */
+	if (regcomp(preg, s, cflags)) {
+		cflags &= ~REG_EXTENDED;
+		xregcomp(preg, s, cflags);
+	}
 	nvfree(v);
 	return preg;
 }
diff --git a/testsuite/awk.tests b/testsuite/awk.tests
index 953a6e5..8e72dd3 100755
--- a/testsuite/awk.tests
+++ b/testsuite/awk.tests
@@ -22,6 +22,11 @@ testing "awk hex const 1" "awk '{ print or(0xffffffff,1) }'" "4.29497e+09\n" ""
 testing "awk hex const 2" "awk '{ print or(0x80000000,1) }'" "2.14748e+09\n" "" "\n"
 testing "awk oct const"   "awk '{ print or(01234,1) }'"      "669\n"         "" "\n"
 
+# '@(samp|code|file)\{' is an invalid extended regex (unmatched '{'),
+# but gawk 3.1.5 does not bail out on it.
+testing "awk gsub falls back to non-extended-regex" \
+	"awk 'gsub(\"@(samp|code|file)\{\",\"\");'; echo \$?" "0\n" "" "Hi\n"
+
 tar xjf awk_t1.tar.bz2
 testing "awk 'gcc build bug'" \
 	"awk -f awk_t1_opt-functions.awk -f awk_t1_opth-gen.awk <awk_t1_input | md5sum" \