minifi-cpp: Fix build with clang

Disable c++11-narrowing-const-reference warning as error
Fixes
git/extensions/standard-processors/utils/JoltUtils.cpp:498:23: error: non-constant-expression cannot be narrowed from type 'unsigned long long' to 'unsigned int' in initializer list [-Wc++11-narrowing-const-reference]

return ResultT{{std::stoull(std::string{idx_begin, it}), {}}, it};
                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Khem Raj <raj.khem@gmail.com>

meta-oe/recipes-extended/minifi-cpp/minifi-cpp_0.99.1.bb

@@ -66,6 +66,7 @@ DEPENDS = "virtual/crypt bison-native flex-native flex openssl curl zlib xz bzip
 
 OECMAKE_FIND_ROOT_PATH_MODE_PROGRAM = "BOTH"
 
+CXXFLAGS:append:toolchain-clang = " -Wno-error=c++11-narrowing-const-reference"
 LDFLAGS:append:riscv32 = " -latomic"
 
 EXTRA_OECMAKE = " \