diff --git a/contrib/netbsd-tests/lib/libc/regex/README b/contrib/netbsd-tests/lib/libc/regex/README
index 6d9a28cf60c..0e8a09a764f 100644
--- a/contrib/netbsd-tests/lib/libc/regex/README
+++ b/contrib/netbsd-tests/lib/libc/regex/README
@@ -28,6 +28,7 @@ The full list of flags:
   $	REG_NOTEOL
   #	REG_STARTEND (see below)
   p	REG_PEND
+  P	REG_POSIX
 
 For REG_STARTEND, the start/end offsets are those of the substring
 enclosed in ().
diff --git a/contrib/netbsd-tests/lib/libc/regex/data/meta.in b/contrib/netbsd-tests/lib/libc/regex/data/meta.in
index b8f14aad8c7..30085a8d1e9 100644
--- a/contrib/netbsd-tests/lib/libc/regex/data/meta.in
+++ b/contrib/netbsd-tests/lib/libc/regex/data/meta.in
@@ -5,7 +5,7 @@ a\*c		&	a*c	a*c
 a\\b		&	a\b	a\b
 a\\\*b		&	a\*b	a\*b
 # Begin FreeBSD
-a\bc		&	abc
+a\bc		&CP	EESCAPE
 # End FreeBSD
 a\		&C	EESCAPE
 a\\bc		&	a\bc	a\bc
diff --git a/contrib/netbsd-tests/lib/libc/regex/main.c b/contrib/netbsd-tests/lib/libc/regex/main.c
index eac4e2d9b51..243c8dc5ff8 100644
--- a/contrib/netbsd-tests/lib/libc/regex/main.c
+++ b/contrib/netbsd-tests/lib/libc/regex/main.c
@@ -338,7 +338,7 @@ options(int type, char *s)
 {
 	char *p;
 	int o = (type == 'c') ? copts : eopts;
-	const char *legal = (type == 'c') ? "bisnmp" : "^$#tl";
+	const char *legal = (type == 'c') ? "bisnmpP" : "^$#tl";
 
 	for (p = s; *p != '\0'; p++)
 		if (strchr(legal, *p) != NULL)
@@ -362,6 +362,9 @@ options(int type, char *s)
 			case 'p':
 				o |= REG_PEND;
 				break;
+			case 'P':
+				o |= REG_POSIX;
+				break;
 			case '^':
 				o |= REG_NOTBOL;
 				break;