Compiling on RHEL  6.9.

Because of the higher curl depenancy, I am using the optional httpd24-curl packages.

httpd24-libcurl-7.47.1-1.1.el6.x86_64

httpd24-curl-7.47.1-1.1.el6.x86_64

httpd24-libcurl-devel-7.47.1-1.1.el6.x86_64

Which get installed in /opt/rh/httpd24. Usual procedure is to "enable" thier use by sourcing /opt/rh./httpd24/enable, which sets PATH, LD_LIBRARY_PATH and other related items to make sure you are using the right version. In this case, an LD_LIBRARY_PATH that includes

/opt/rh/httpd24/root/usr/lib64

When compiling, I got the following error while linking zabbix_server

../../src/libs/zbxhistory/libzbxhistory.a(history_elastic.o): In function `elastic_writer_flush':
/opt/sysadmin/accounts/aladen/src/zabbix/zabbix-3.4.13/src/libs/zbxhistory/history_elastic.c:457: undefined reference to `curl_multi_wait'
collect2: ld returned 1 exit status

 Which lead me to look at the linker flags.

Looked in the Makefile that was generated for zabbix_server. Noticed that

LIBCURL_LDFLAGS was not set. So I manually set it. (interestingly enough, LIBCURL_CFLAGS was set properly, so it was compiling against the right curl, just not linking against it.

LIBCURL_LDFLAGS = -L/opt/rh/httpd24/root/usr/lib64

Tried again. Same error. So I looked a little closer
Noticed that "zabbix_server_LDFLAGS" doesn't actually use LIBCURL_LDFLAGS.
So I manually updated that

zabbix_server_LDFLAGS =    -L/opt/rh/httpd24/root/usr/lib64 -L/opt/rh/postgresql92/root/usr/lib64      -L/usr/lib64 -L/usr/lib   -L/usr/lib -L/usr/lib

After which it compiled sucessfully.

So the bug is that when configure builds the makefile for zabbix_server it should account for an alternate location of libcurl in both the compile and the linking.