Remove patch for opencl-c.h (#391)

Not all functions that use Image type should be wrapped by
feature macro __opencl_c_images because some of these functions
need to be available for OpenCL C 1.2 in which feature macro can not be
set.
Therefore this patch needs to be removed because it broke backward
compatibility for OpenCL C 1.2

Additionally, fixed cross-compilation crash. The bug was added by PR
#379

Author: mnaczk

cl_headers/CMakeLists.txt

@@ -3,7 +3,6 @@ set(CLANG_COMMAND $<TARGET_FILE:clang> )
 if(LLVM_USE_HOST_TOOLS AND NOT OPENCL_CLANG_BUILD_EXTERNAL)
   build_native_tool(clang CLANG_COMMAND)
 endif()
-set(LINUX_RESOURCE_LINKER_COMMAND linux_resource_linker)
 
 function(copy_file SRC DST)
 add_custom_command(