[libclc] Allow default path when looking for llvm-spirv

This is an external tool, so I don't think there is an expectation
that it has to be in the LLVM tools bindir. It may also be in the
default system bindir (which is not necessarily the same).

Author: nikic

libclc/CMakeLists.txt

@@ -114,7 +114,7 @@ endforeach()
 if( TARGET llvm-spirv )
   get_host_tool_path( llvm-spirv LLVM_SPIRV llvm-spirv_exe llvm-spirv_target )
 else()
-  find_program( LLVM_SPIRV llvm-spirv PATHS ${LLVM_TOOLS_BINARY_DIR} NO_DEFAULT_PATH )
+  find_program( LLVM_SPIRV llvm-spirv PATHS ${LLVM_TOOLS_BINARY_DIR} )
   set( llvm-spirv_exe "${LLVM_SPIRV}" )
   set( llvm-spirv_target )
 endif()