Bug#881054: clblas: "unknown argument: -g" on beignet (Intel)

[Rebecca N. Palmer]

Control: forcemerge -1 886327
Control: retitle -1 clblas: "unknown argument: -g" on beignet (Intel)
Control: reassign -1 clblas2,beignet-opencl-icd
Control: tags -1 patch

This is technically a bug in _beignet_, since -g is a required option 
for OpenCL 2.0 (but not 1.x) ICDs, but applying the above patch to 
clblas might be easier.

There is a second bug here that is in clblas: this, and potentially 
other build failures, is a _crash_ (rather than an error return) because 
clblas tries to cache the result before checking for failure (NULL). 
Fix for this part:

--- a/src/library/blas/generic/common2.cc
+++ b/src/library/blas/generic/common2.cc
@@ -85,9 +85,11 @@ extern "C" Kernel* makeKernelCached(cl_device_id device,
                                       buildOpts,
                                       error);

-        bl.setProgram(kernel->program);
-
-        bl.populateCache();
+        if (kernel != NULL)
+        {
+            bl.setProgram(kernel->program);
+            bl.populateCache();
+        }

          return kernel;
      }

Note that even after applying these, you may not get far before running 
into #877316 (unrequested use of double precision, which beignet doesn't 
support).  If you just want to use clblas, it may be easier to install 
Intel's new OpenCL driver (not in Debian yet): 
https://01.org/compute-runtime