# uname -ar
Linux vs00358-27 2.6.32-696.1.1.el6.x86_64 #1 SMP Tue Apr 11 17:13:24 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

# cat /etc/redhat-release
CentOS release 6.9 (Final)

# wget https://github.com/sahlberg/libiscsi/archive/1.18.0.tar.gz
# mv 1.18.0.tar.gz libiscsi-1.18.0.tar.gz
# tar -xvf libiscsi-1.18.0.tar.gz -C /usr/local/src/
# mv /usr/local/src/libiscsi-1.18.0/ /usr/src/libiscsi-1.18.0/
# vi /usr/src/libiscsi-1.18.0/dkms.conf
PACKAGE_NAME="libiscsi"
PACKAGE_VERSION="1.18.0"
BUILT_MODULE_NAME[0]="libiscsi"
DEST_MODULE_LOCATION[0]="/kernel/drivers/scsi/"
AUTOINSTALL="yes"

# dkms add -m libiscsi -v 1.18.0
Creating symlink /var/lib/dkms/libiscsi/1.18.0/source ->
                 /usr/src/libiscsi-1.18.0

DKMS: add completed.

# dkms build -m libiscsi -v 1.18.0

Kernel preparation unnecessary for this kernel.  Skipping...

Building module:
cleaning build area...(bad exit status: 2)
make -j1 KERNELRELEASE=2.6.32-696.1.1.el6.x86_64 -C /lib/modules/2.6.32-696.1.1.el6.x86_64/build M=/var/lib/dkms/libiscsi/1.18.0/build...(bad exit status: 2)
Error! Bad return status for module build on kernel: 2.6.32-696.1.1.el6.x86_64 (x86_64)
Consult /var/lib/dkms/libiscsi/1.18.0/build/make.log for more information.

# cat /var/lib/dkms/libiscsi/1.18.0/build/make.log
DKMS make.log for libiscsi-1.18.0 for kernel 2.6.32-696.1.1.el6.x86_64 (x86_64)
Mon Jan 22 06:31:47 +07 2018
make: Entering directory `/usr/src/kernels/2.6.32-696.1.1.el6.x86_64'
scripts/Makefile.build:44: /var/lib/dkms/libiscsi/1.18.0/build/Makefile: No such file or directory
make[1]: *** No rule to make target `/var/lib/dkms/libiscsi/1.18.0/build/Makefile'.  Stop.
make: *** [_module_/var/lib/dkms/libiscsi/1.18.0/build] Error 2
make: Leaving directory `/usr/src/kernels/2.6.32-696.1.1.el6.x86_64'