opengl: Only apply VirtualGL fixup when we are a runtime dependency

pkgs/opengl/insert-virtualgl.sh

@@ -240,6 +240,8 @@ EOF
 # Find all executables that depend on libGL and replace with a wrapper script that either executes the original
 # executable or a copy with an added libvglfaker.so dependency depending on whether VGL_DISPLAY is set or not.
 #
+# Only run when we are a runtime dependency (i.e., our host matches).
+#
 VGL_autoAddVGL() {
   declare opts=$(shopt -p) output
   set +o pipefail
@@ -255,4 +257,7 @@ VGL_autoAddVGL() {
   eval "$opts"
 }
 
-postFixupHooks+=(VGL_autoAddVGL)
+
+if (( hostOffset == 0 )); then
+  fixupOutputHooks+=(VGL_autoAddVGL)
+fi