cmake HAVE_DECL_INITGROUPS2 examples

nghttp2/nghttp2 CMakeLists.txt :392 

check_symbol_exists(initgroups unistd.h HAVE_DECL_INITGROUPS2)

fluent/fluent-bit lib/nghttp2-1.65.0/CMakeLists.txt :376 

check_symbol_exists(initgroups unistd.h HAVE_DECL_INITGROUPS2)