Fixes to dpctl-post-link prior changes gh-1081

conda prunes empty folders, so the dpctl tar-ball did not contain
empty etc/OpenCL/vendors folder. Solved by create a dummy `.dpctl_readme`
file in that folder.

The script dpctl-post-link.sh contained a type in the filename it was checking
should not exist.

Author: oleksandr-pavlyk

conda-recipe/build.sh

@@ -33,5 +33,6 @@ fi
 
 # need to create this folder so ensure that .dpctl-post-link.sh can work correctly
 mkdir -p $PREFIX/etc/OpenCL/vendors
+echo "dpctl creates symbolic link to system installed /etc/OpenCL/vendors/intel.icd as a work-around." > $PREFIX/etc/OpenCL/vendors/.dpctl_readme
 
 cp $RECIPE_DIR/dpctl-post-link.sh $PREFIX/bin/.dpctl-post-link.sh

conda-recipe/dpctl-post-link.sh

@@ -2,7 +2,8 @@
 
 systemwide_icd=/etc/OpenCL/vendors/intel.icd
 local_vendors=$CONDA_PREFIX/etc/OpenCL/vendors/
+icd_fn=$local_vendors/intel-ocl-gpu.icd
 
-if [[ -f $systemwide_icd && -d $local_vendors && ! -f $local_vendors/intl-ocl-gpu.icd ]]; then
-    ln -s $systemwide_icd  $local_vendors/intel-ocl-gpu.icd
+if [[ -f $systemwide_icd && -d $local_vendors && ! -f $icd_fn ]]; then
+    ln -s $systemwide_icd $icd_fn
 fi