add /usr/lib/cuda to the CUDA toolkit search paths

Thanks to Andreas Beckmann for the patch (Closes: #882505)

debian/changelog

@@ -14,6 +14,8 @@ llvm-toolchain-snapshot (1:6.0~svn315736-2) unstable; urgency=medium
     Many thanks to Adrian Bunk for that
   * Use ?= for some variables declarations
   * Remove the hardcoded declarations of llvm version in debian/rules
+  * add /usr/lib/cuda to the CUDA toolkit search paths
+    Thanks to Andreas Beckmann for the patch (Closes: #882505)
 
  -- Sylvestre Ledru <sylvestre@debian.org>  Mon, 16 Oct 2017 10:24:33 +0200
 

debian/patches/series

@@ -45,3 +45,5 @@ disable-error-xray.diff
 lldb-disable-swig-error.diff
 silent-test-macho.diff
 silent-llvm-isel-fuzzer.diff
+update-cuda-search-path.patch
+

debian/patches/update-cuda-search-path.patch

@@ -0,0 +1,24 @@
+Author: Andreas Beckmann <anbe@debian.org>
+Description: add /usr/lib/cuda to CUDA search paths
+ nvidia-cuda-toolkit/non-free now provides a shim monolitic cuda install
+ tree in /usr/lib/cuda (LP: #1706326) that could be used for
+   clang++ --cuda-path=/usr/lib/cuda
+
+ let clang try that path by default, too, s.t. an explicit --cuda-path is
+ not needed for the nvidia-cuda-toolkit/non-free packages
+ 
+ try the new path *after* the default paths /usr/local/cuda{,-X.Y}
+ to not interfere with cuda installations from nvidia's installer
+
+Index: llvm-toolchain-5.0-5.0.1~+rc1/clang/lib/Driver/ToolChains/Cuda.cpp
+===================================================================
+--- llvm-toolchain-5.0-5.0.1~+rc1.orig/clang/lib/Driver/ToolChains/Cuda.cpp
++++ llvm-toolchain-5.0-5.0.1~+rc1/clang/lib/Driver/ToolChains/Cuda.cpp
+@@ -71,6 +71,7 @@ CudaInstallationDetector::CudaInstallati
+     CudaPathCandidates.push_back(D.SysRoot + "/usr/local/cuda");
+     for (const char *Ver : Versions)
+       CudaPathCandidates.push_back(D.SysRoot + "/usr/local/cuda-" + Ver);
++    CudaPathCandidates.push_back(D.SysRoot + "/usr/lib/cuda");
+   }
+ 
+   for (const auto &CudaPath : CudaPathCandidates) {