Use getopt in the bsc_hack to parse options

Current options include a draft of the help screen, an option
to disable the colors and to specify the debug categories to
show.
diff --git a/include/openbsc/debug.h b/include/openbsc/debug.h
index dcb74c0..018a116 100644
--- a/include/openbsc/debug.h
+++ b/include/openbsc/debug.h
@@ -19,5 +19,6 @@
 
 void debugp(unsigned int subsys, char *file, int line, const char *format, ...);
 void debug_parse_category_mask(const char* mask);
+void debug_use_color(int use_color);
 
 #endif /* _DEBUG_H */