build: FAILED conformance/interfaces/sigset/6-1: build: FAILED: Compiler output: conformance/interfaces/sigset/6-1.c:45:13: warning: implicit declaration of function 'sigset' is invalid in C99 [-Wimplicit-function-declaration] if (sigset(SIGCHLD,SIG_HOLD) != SIG_HOLD) { ^ conformance/interfaces/sigset/6-1.c:45:28: error: use of undeclared identifier 'SIG_HOLD' if (sigset(SIGCHLD,SIG_HOLD) != SIG_HOLD) { ^ conformance/interfaces/sigset/6-1.c:45:41: error: use of undeclared identifier 'SIG_HOLD' if (sigset(SIGCHLD,SIG_HOLD) != SIG_HOLD) { ^ 1 warning and 2 errors generated.