libc: Add stubs for signal() and raise()

libs/libc/include/signal.h

@@ -6,4 +6,16 @@ typedef int sig_atomic_t; // On the x86, writes to aligned 32-bit and 64-bit int
 
 #define SIGINT 1 // Not implemented.
 
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+    void (*signal(int sig, void (*func)(int)))(int); // Not implemented.
+    int raise(int sig);                              // Not implemented.
+
+#ifdef __cplusplus
+}
+#endif
+
 #endif

libs/libc/src/signal.cpp

@@ -0,0 +1,15 @@
+#include <luna.h>
+#include <signal.h>
+
+extern "C"
+{
+    void (*signal(int, void (*)(int)))(int)
+    {
+        NOT_IMPLEMENTED("signal");
+    }
+
+    int raise(int)
+    {
+        NOT_IMPLEMENTED("raise");
+    }
+}