Fwd: Dynamic Kernel Linker compilation issues

[Louis NOMINE]

Hi, 

I'm currently working on a project where I need to create a PCI device driver that can work on freeBSD. In order to learn how o do so I'm using the doccuentation I've found on your website (https://www.freebsd.org/doc/en_US.ISO8859-1/books/arch-handbook/driverbasics-kld.html) 

I have created both files (source code and the makefile). when I try to do a make operation I get the following error : 

make: "/usr/share/mk/bsd.kmod.mk" line 12: Unable to locate the kernel source tree. Set SYSDIR to override. 

I'm using PCBSD 10 and I don't know how to solve my problem. 

Do you know how to help me ? 

Thanks in advance, 

Regards, 

Louis Nominé