opencl-info: fix build

pkgs/tools/system/opencl-info/default.nix

@@ -10,6 +10,14 @@ stdenv.mkDerivation {
     sha256 = "114lxgnjg40ivjjszkv4n3f3yq2lbrvywryvbazf20kqmdz7315l";
   };
 
+  patches = [
+    # The cl.hpp header was removed from opencl-clhpp. This patch
+    # updates opencl-info to use the new cp2.hpp header.
+    #
+    # Submitted upstream: https://github.com/marchv/opencl-info/pull/2
+    ./opencl-info-clhpp2.diff
+  ];
+
   buildInputs = [ opencl-clhpp ocl-icd ];
 
   NIX_LDFLAGS = "-lOpenCL";

pkgs/tools/system/opencl-info/opencl-info-clhpp2.diff

@@ -0,0 +1,22 @@
+diff --git a/opencl-info.cpp b/opencl-info.cpp
+index a23015d..a6de0c1 100644
+--- a/opencl-info.cpp
++++ b/opencl-info.cpp
+@@ -7,7 +7,7 @@
+ #if defined(__APPLE__) || defined(__MACOSX)
+ #  include <OpenCL/cl.hpp>
+ #else
+-#  include <CL/cl.hpp>
++#  include <CL/cl2.hpp>
+ #endif
+ 
+ #include <iostream>
+@@ -130,7 +130,7 @@ int main() {
+                 PconstEnd;
+                 P(device, CL_DEVICE_LOCAL_MEM_SIZE);
+                 Pbool(device, CL_DEVICE_ERROR_CORRECTION_SUPPORT);
+-                Pbool(device, CL_DEVICE_HOST_UNIFIED_MEMORY);
++                // Pbool(device, CL_DEVICE_HOST_UNIFIED_MEMORY); /* Deprecated in 2.0 */
+                 P(device, CL_DEVICE_PROFILING_TIMER_RESOLUTION);
+                 Pbool(device, CL_DEVICE_ENDIAN_LITTLE);
+                 Pbool(device, CL_DEVICE_AVAILABLE);