--- blam.in
+++ blam.in
@@ -6,7 +6,7 @@
 MOZILLA_FIVE_HOME=@MOZILLA_HOME@
 export MOZILLA_FIVE_HOME
 
-LD_LIBRARY_PATH="@prefix@/lib/blam:@MOZILLA_HOME@:$LD_LIBRARY_PATH"
+LD_LIBRARY_PATH="@prefix@/lib/blam:@MOZILLA_HOME@${LD_LIBRARY_PATH+:$LD_LIBRARY_PATH}"
 export LD_LIBRARY_PATH
 
 exec mono @prefix@/lib/blam/blam.exe $@