diff -ur avogadro-1.2.0/libavogadro/src/extensions/symmetry/libmsym/src/orbital.c avogadro-1.2.0.build/libavogadro/src/extensions/symmetry/libmsym/src/orbital.c
--- avogadro-1.2.0/libavogadro/src/extensions/symmetry/libmsym/src/orbital.c	2016-06-08 16:19:45.000000000 +0200
+++ avogadro-1.2.0.build/libavogadro/src/extensions/symmetry/libmsym/src/orbital.c	2017-04-13 11:56:21.795761712 +0200
@@ -67,13 +67,13 @@
         }
         case 2 : {
             //o->v = dpolynomial[m+l];
-            char *d = (signbit(m) == 1 ? "-" : "+");
+            char *d = (m < 0 ? "-" : "+");
             snprintf(o->name, sizeof(o->name), "%dd%d%s",n,abs(m),d);
             break;
         }
         default : {
             char t = 'f' - 3 + l;
-            char *d = (signbit(m) == 1 ? "-" : "+");
+            char *d = (m < 0 ? "-" : "+");
             snprintf(o->name, sizeof(o->name), "%d%c%d%s",n,t,abs(m),d);
         }
     }