package/postgresql: fix build with external gettext

Postgresql fails to build with NLS enabled against uclibc/musl after the
move to meson:

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/home/autobuild/autobuild/instance-13/output-1/host/lib/gcc/aarch64-buildroot-linux-uclibc/12.4.0/../../../../aarch64-buildroot-linux-uclibc/bin/ld: scram-common.c:(.text+0x65c): undefined reference to `libintl_gettext'
/home/autobuild/autobuild/instance-13/output-1/host/lib/gcc/aarch64-buildroot-linux-uclibc/12.4.0/../../../../aarch64-buildroot-linux-uclibc/bin/ld: scram-common.c:(.text+0x6cc): undefined reference to `libintl_gettext'
/home/autobuild/autobuild/instance-13/output-1/host/lib/gcc/aarch64-buildroot-linux-uclibc/12.4.0/../../../../aarch64-buildroot-linux-uclibc/bin/ld: scram-common.c:(.text+0x73c): undefined reference to `libintl_gettext'
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uclibc/musl toolchains use GNU gettext for NLS support.
So we need to link against external libintl.

Fixes: https://autobuild.buildroot.org/results/244f154aece46d02747b875faba4c51e7b5d0dc2/
Signed-off-by: Maxim Kochetkov <fido_max@inbox.ru>
[Peter: also pass TARGET_LDFLAGS, mention the change to meson]
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/postgresql/postgresql.mk

@@ -13,7 +13,7 @@ POSTGRESQL_CPE_ID_VENDOR = postgresql
 POSTGRESQL_SELINUX_MODULES = postgresql
 POSTGRESQL_INSTALL_STAGING = YES
 POSTGRESQL_CONFIG_SCRIPTS = pg_config
-POSTGRESQL_CONF_ENV = LIBS=$(TARGET_NLS_LIBS)
+POSTGRESQL_LDFLAGS = $(TARGET_LDFLAGS) $(TARGET_NLS_LIBS)
 # We have to force invalid paths for xmllint and xsltproc, otherwise
 # if detected they get used, even with -Ddocs=disabled and
 # -Ddocs_pdf=disabled, and it causes build failures