Correct paths.

Index: gigalomania.desktop
--- gigalomania.desktop.orig
+++ gigalomania.desktop
@@ -1,8 +1,8 @@
 [Desktop Entry]
 Name=Gigalomania
 Comment=2D RTS Game
-Exec=/opt/gigalomania/gigalomania
-Path=/opt/gigalomania/
+Exec=${TRUEPREFIX}/bin/gigalomania
+Path=${TRUEPREFIX}/share/gigalomania
 Terminal=false
 Type=Application
 Icon=gigalomania64
