Implement proc_remove_breakpoint
diff --git a/proc.h b/proc.h
index 9939c4e..ed2bb70 100644
--- a/proc.h
+++ b/proc.h
@@ -215,8 +215,9 @@
/* Insert BP into PROC. */
int proc_add_breakpoint(struct Process *proc, struct breakpoint *bp);
-/* Remove BP from PROC. */
-int proc_remove_breakpoint(struct Process *proc, struct breakpoint *bp);
+/* Remove BP from PROC. This has no reason to fail in runtime. If it
+ * does not find BP in PROC, it's hard error guarded by assertion. */
+void proc_remove_breakpoint(struct Process *proc, struct breakpoint *bp);
/* Iterate through the libraries of PROC. See each_process for
* detailed description of the iteration interface. */