main/pgpool: fix build

not sure what changed with the headers,
but 3.21 builders found a missing include

main/pgpool/APKBUILD

@@ -24,6 +24,7 @@ pkggroups="postgres"
 install="$pkgname.pre-install $pkgname.post-upgrade"
 subpackages="$pkgname-openrc $pkgname-doc $pkgname-static $pkgname-dev"
 source="https://github.com/pgpool/pgpool2/archive/V$_pkgver/pgpool2-$_pkgver.tar.gz
+	missing-include.patch
 	$pkgname.initd
 	$pkgname.confd
 	$pkgname.logrotated
@@ -89,6 +90,7 @@ doc() {
 
 sha512sums="
 6db9487f2b1474f357f6afb6e4d0c65a8ad4c606362caa7d9aecd7ce36f5d61a8363f3d5e721b4e55eb32ebe5722285ae28439f671407e5532e9612b9e5211c1  pgpool2-4_5_2.tar.gz
+2d7780d7e9faf2b4bc83060e8d3cd56543afa6300ea2f3ea390c1eca01acacc0132f82da49978ffa6876c86e6a25971f146c71d44d41a8dbedccdc3935aa9dc6  missing-include.patch
 9e54835f2a907f4b7a521d7d52cf04f69e1edfe591d9618cb2a1514953e5ba9e0d5ef543f0d6ee281fef21e64b7a6ff4a26a7f54fadbfc2d3bc7009d10dbccbf  pgpool.initd
 7e605cea31ae32127ec1aca9e47a6652e87243214bde202d49a405652784e68b4dbff7d364345259d327bc37041c60c146e6f674a4aa72c6214bdba3740e700e  pgpool.confd
 c9aa2ea9484ed29cb57cdff4004fa9dd4780d73c69db3378effb2e0ecd3ae178771c6a847a28e1a9cc6492ada4321584afb92c9b592119fb11898b42191f22b1  pgpool.logrotated

main/pgpool/missing-include.patch

+diff --git a/src/parser/snprintf.c b/src/parser/snprintf.c
+index 0e52839..f0368f3 100644
+--- a/src/parser/snprintf.c
++++ b/src/parser/snprintf.c
+@@ -43,6 +43,7 @@
+ #include <string.h>
+ #include <ctype.h>
+ #include <errno.h>
++#include <math.h> // isnan
+ #include "pool_parser.h"
+ #include "stringinfo.h"
+ #include "utils/palloc.h"