SIG_USR handling seems to be working

git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@282 b08c6af1-5177-4d33-ba66-4b1c6b8b522a

C/init.c

@@ -874,6 +874,9 @@ InitCodes(void)
   AtomArrow = LookupAtom("->");
   heap_regs->atom_assert = LookupAtom(":-");
   heap_regs->atom_alarm = LookupAtom("$alarm");
+#if USE_SIGACTION
+  heap_regs->atom_sig_pending = LookupAtom("$sig_pending");
+#endif
   AtomBraces = LookupAtom("{}");
   heap_regs->atom_b = LookupAtom("$last_choice_pt");
   heap_regs->atom_break = LookupAtom("$break");