Looks for the 'CL' library when OpenCL is a headers-only library

[yurivict]

Failure:

configure:32789: c++ -std=gnu++17 -o conftest -O2 -pipe -fno-omit-frame-pointer -fstack-protector-strong -isystem /usr/local/include -fno-strict-aliasing -fno-omit-frame-pointer  -isystem /usr/local/include  -Wall -D_THREAD_SAFE -pthread  -fno-omit-frame-pointer -isystem /usr/local/include  conftest.cpp -lCL  -lm -L/usr/local/lib >&5
ld: error: unable to find library -lCL
c++: error: linker command failed with exit code 1 (use -v to see invocation)

OpenCL is a headers-only library.