graphics/vulkan-loader: unbreak without /usr/bin/as on amd64/i386
CMake Error at loader/CMakeLists.txt:151 (enable_language):
No CMAKE_ASM-ATT_COMPILER could be found. Tell CMake where to find the compiler by setting either the environment variable "ASM-ATT" or the CMake cache entry CMAKE_ASM-ATT_COMPILER to the full path to the compiler, or to the compiler name if it is in the PATH.
PR: 205250
Reported by: antoine (via exp-run)