Os:

rehl 7.5

Zabbix:

6.4

Steps to reproduce:

1. https://www.zabbix.com/documentation/6.4/en/manual/installation/install
2. export CFLAGS="-std=gnu99"
3. ./configure --enable-server --with-postgresql --with-net-snmp

Result:
checking for unsetenv... yes
checking for sigqueue... yes
checking for round... yes
checking for /proc filesystem... yes
checking for file /proc/stat... yes
checking for file /proc/cpuinfo... yes
checking for file /proc/0/psinfo... no
checking for file /proc/loadavg... yes
checking for file /proc/net/dev... yes
checking for long long format... no
checking for -rdynamic linking option... yes
checking for libperfstat 5.2.0.40 fileset... no
checking for libperfstat 5.3.0.60 fileset... no
checking for architecture... linux (linux-gnu)
checking for the linux kernel version... unknown family (3.10.0-862.el7.x86_64)
checking size of void *... 8
checking for Oracle support... no
checking for pg_config... no
configure: error: PostgreSQL library not found

Expected: