Index: bsd.ruby.mk
===================================================================
--- bsd.ruby.mk	(revision 358766)
+++ bsd.ruby.mk	(working copy)
@@ -523,6 +523,16 @@
 RUBY_EXTCONF?=		extconf.rb
 CONFIGURE_ARGS+=	--with-opt-dir="${LOCALBASE}"
 
+.if defined(UID)
+_uid=			${UID}
+.else
+_uid!=			${ID} -u
+.endif
+.if ${_uid} != 0
+CONFIGURE_ENV+=		RB_USER_INSTALL=yes
+.endif
+.undef _uid
+
 do-configure:	ruby-extconf-configure
 
 ruby-extconf-configure: