cmake HAVE_DECL_STRNLEN examples

ValveSoftware/vogl src/libbacktrace/CMakeLists.txt :151 

check_function_exists (strnlen HAVE_DECL_STRNLEN)

Bitcoin-ABC/bitcoin-abc src/config/CMakeLists.txt :135 

check_symbol_exists(strnlen "string.h" HAVE_DECL_STRNLEN)

bitcoin-sv/bitcoin-sv src/config/CMakeLists.txt :117 

check_symbol_exists(strnlen "string.h" HAVE_DECL_STRNLEN)