Add build system scaffolding and libc headers

1 files changed, 18 insertions, 0 deletions

diff --git a/lib/libc/signal/sigismember.c b/lib/libc/signal/sigismember.c
new file mode 100644
index 00000000..8adf5fab
--- /dev/null
+++ b/lib/libc/signal/sigismember.c
@@ -0,0 +1,18 @@
+#include <asm-generic/signal.h>
+
+typedef __UINT64_TYPE__ __sigset_t;
+
+#define __sigmask(sig) (((__sigset_t)1) << ((sig) - 1))
+#define __sigismember(set, sig)                     \
+	(__extension__({                            \
+		__sigset_t __mask = __sigmask(sig); \
+		*(set) & __mask ? 1 : 0;            \
+	}))
+
+int sigismember(const __sigset_t *set, int signo)
+{
+	if (signo < 1 || signo > _NSIG)
+		return -1;
+
+	return __sigismember((const __sigset_t *)set, signo);
+}