devel/spirv-llvm-translator: unbreak build with clang 16

In file included from lib/SPIRV/LLVMToSPIRVDbgTran.cpp:38:
In file included from lib/SPIRV/LLVMToSPIRVDbgTran.h:42:
In file included from lib/SPIRV/libSPIRV/SPIRVModule.h:44:
In file included from lib/SPIRV/libSPIRV/SPIRVEntry.h:44:
In file included from lib/SPIRV/libSPIRV/SPIRVEnum.h:44:
In file included from lib/SPIRV/libSPIRV/SPIRVOpCode.h:45:
lib/SPIRV/libSPIRV/spirv_internal.hpp:182:5: error: integer value 16777216 is outside the valid range of values [0, 16777215] for the enumeration type 'LoopControlMask' [-Wenum-constexpr-conversion]
    static_cast<LoopControlMask>(ILoopControlLoopCountINTELMask);
    ^

Reported by:	pkg-fallout
Regressed by:	llvm/llvm-project@b36453530418
See also:	KhronosGroup/SPIRV-LLVM-Translator@1d5694629aad

devel/spirv-llvm-translator/Makefile

@@ -32,6 +32,7 @@ GH_TUPLE_llvm15=KhronosGroup:SPIRV-Headers:1.5.4.raytracing.fixed-168-g5a12186:h
 GH_TUPLE_llvm14=KhronosGroup:SPIRV-Headers:1.5.4.raytracing.fixed-124-g20b02de:headers/projects/SPIRV-Headers
 GH_TUPLE_llvm13=KhronosGroup:SPIRV-Headers:1.5.4.raytracing.fixed-83-gddf3230:headers/projects/SPIRV-Headers
 DISTINFO_FILE=	${.CURDIR}/distinfo.${FLAVOR}
+CXXFLAGS+=	${${FLAVOR:S/llvm//} < 16 && ${COMPILER_TYPE} == clang && ${COMPILER_VERSION} >= 160:?-Wno-enum-constexpr-conversion:}
 CMAKE_ON=	BUILD_SHARED_LIBS LLVM_BUILD_TOOLS LLVM_TOOL_SPIRV_HEADERS_BUILD
 CMAKE_ARGS=	-DLLVM_DIR:PATH="${LOCALBASE}/${FLAVOR}"
 CMAKE_INSTALL_PREFIX=		${PREFIX}/${FLAVOR}