When you specify the location of package with configure option --with-package (e. g. --with-ssh2=/root/libssh2-1.2.8-install) and there is another one installed in the standard location of the system (/usr) compilation will use the one in the system. Take this example:

(libssh2 version 0.17 in the system)

1. rpm -q libssh2-devel
   libssh2-devel-0.17

1. rpm -ql libssh2-devel | grep "\.so"
   /usr/lib64/libssh2.so

(libssh2 version 1.2.8 in /root)

1. ls /root/libssh2-1.2.8-install/lib/libssh2.so
   /root/libssh2-1.2.8-install/lib/libssh2.so

1. ./configure --enable-server --with-ssh2=/root/libssh2-1.2.8-install --with-mysql

Configure passes check for libssh2 version > 1.0 so it uses the one in /root . Next we run make:

[...]
gcc -g -O2 -I/usr/include/mysql -g -pipe -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -fno-strict-aliasing -fwrapv -I/root/libssh2-1.2.8-install/include -rdynamic -o zabbix_server -L/usr/lib64/mysql -L/usr/lib64 -L/root/libssh2-1.2.8-install/lib zabbix_server-actions.o zabbix_server-operations.o zabbix_server-events.o zabbix_server-zlog.o zabbix_server-server.o alerter/libzbxalerter.a dbsyncer/libzbxdbsyncer.a dbconfig/libzbxdbconfig.a discoverer/libzbxdiscoverer.a pinger/libzbxpinger.a poller/libzbxpoller.a housekeeper/libzbxhousekeeper.a timer/libzbxtimer.a trapper/libzbxtrapper.a nodewatcher/libzbxnodewatcher.a utils/libzbxutils.a httppoller/libzbxhttppoller.a watchdog/libzbxwatchdog.a escalator/libzbxescalator.a proxypoller/libzbxproxypoller.a selfmon/libzbxselfmon.a ../../src/libs/zbxsysinfo/libzbxserversysinfo.a ../../src/libs/zbxsysinfo/linux/libspecsysinfo.a ../../src/libs/zbxsysinfo/common/libcommonsysinfo.a ../../src/libs/zbxsysinfo/simple/libsimplesysinfo.a ../../src/libs/zbxlog/libzbxlog.a ../../src/libs/zbxdbcache/libzbxdbcache.a ../../src/libs/zbxmemory/libzbxmemory.a ../../src/libs/zbxalgo/libzbxalgo.a ../../src/libs/zbxnix/libzbxnix.a ../../src/libs/zbxsys/libzbxsys.a ../../src/libs/zbxconf/libzbxconf.a ../../src/libs/zbxmedia/libzbxmedia.a ../../src/libs/zbxcommon/libzbxcommon.a ../../src/libs/zbxcrypto/libzbxcrypto.a ../../src/libs/zbxcomms/libzbxcomms.a ../../src/libs/zbxcommshigh/libzbxcommshigh.a ../../src/libs/zbxjson/libzbxjson.a ../../src/libs/zbxexec/libzbxexec.a ../../src/libs/zbxself/libzbxself.a ../../src/libs/zbxserver/libzbxserver.a ../../src/libs/zbxicmpping/libzbxicmpping.a ../../src/libs/zbxdbhigh/libzbxdbhigh.a ../../src/libs/zbxdb/libzbxdb.a -lmysqlclient -lssh2 -lm -lresolv
poller/libzbxpoller.a(checks_ssh.o): In function `waitsocket':
/root/zabbix_svn/1.8/src/zabbix_server/poller/checks_ssh.c:64: undefined reference to `libssh2_session_block_directions'

Let's check both libs for the function:

1. objdump -T /usr/lib64/libssh2.so | grep libssh2_session_block_directions

1. objdump -T /root/libssh2-1.2.8-install/lib/libssh2.so | grep libssh2_session_block_directions
   0000000000010270 g DF .text 0000000000000007 Base libssh2_session_block_directions

The one in the system is missing the required subroutine. And why is our compilation process using the one from the system? See gcc options in that command above, the -L/usr/lib64 comes before /root/libssh2-1.2.8-install/lib . gcc takes the first it can find and that happens to be the libssh2 in the system, the wrong one.

The solution is to reorder LDFLAGS so that if you specify package path with --with-package configure option these flags should come first.