https://src.fedoraproject.org/rpms/mscgen/blob/rawhide/f/mscgen-0.20-uninitialized-ymax.patch

# Fixes 'ymax' variable initialization
# http://code.google.com/p/mscgen/issues/detail?id=73
--- a/src/main.c
+++ b/src/main.c
@@ -851,6 +851,7 @@
 
     nextYmin = ymin = gOpts.entityHeadGap;
     yskipmax = 0;
+    ymax = 0;
 
     MscResetArcIterator(m);
     do