UniversalLibiconv: libiconv.diff

textproc/libiconv/Portfile

@@ -31 +31 @@
 
 extract.only    ${distname}${extract.suffix}
 
+pre-fetch {
+    if {[variant_isset universal]} {
+        if {![llength [info commands registry_active]]} {
+            return -code error "+universal variant requires MacPorts 1.4"
+        }
+        if {![catch {registry_active libiconv}]} {
+            return -code error "libiconv needs to be deactivated/uninstalled \
+            before +universal variant can be installed"
+        }
+    }
+}
+
 post-patch {
     if {![variant_isset disable_utf8mac]} {
         system "cd ${worksrcpath} && patch -p1 < ${filespath}/utf8mac.diff"