diff -ruN pl-3.1.2-orig/src/pl-prof.c pl-3.1.2/src/pl-prof.c
--- pl-3.1.2-orig/src/pl-prof.c	Thu Aug  6 15:27:22 1998
+++ pl-3.1.2/src/pl-prof.c	Sat Dec 26 15:14:00 1998
@@ -28,7 +28,7 @@
 
 static bool
 startProfiler(int how)
-{ set_sighandler(SIGPROF, profile);
+{/* set_sighandler(SIGPROF, profile); * HACK<short@ucw.cz>: sigblock() not working! */
 
   value.it_interval.tv_sec  = 0;
   value.it_interval.tv_usec = 1;
diff -ruN pl-3.1.2-orig/src/pl-wam.c pl-3.1.2/src/pl-wam.c
--- pl-3.1.2-orig/src/pl-wam.c	Mon Nov 30 16:14:59 1998
+++ pl-3.1.2/src/pl-wam.c	Sat Dec 26 16:00:07 1998
@@ -3139,6 +3139,9 @@
 	if ( false(DEF, SYSTEM) )
 	  clear(FR, FR_NODEBUG);
 
+/* HACK<short@ucw.cz>: Disable automatic garbage collection, use on-demand */
+#define garbageCollect(FR)
+
 #if O_DYNAMIC_STACKS
 	if ( gc_status.requested )
 	{ lTop = (LocalFrame) argFrameP(FR, DEF->functor->arity);