Problem with GLS installation

[VanceREgnet]

Hello,
after running the gls installation procedure i got this message when building a Xcode project :

Apple Mach-O Linker (ld) Error Group
: Linker command failed with exit code 1 (use -v to see invocation)

Before, i set the header search path to /usr/local/include
and other linker flag to -l/usr/local/include -L/usr/local/lib -lgslcblas

I use macOS 10.12.4 and Xcode 8.3

I didn't find any additional information.
Please help, it's urgent.

Uwe