strongswan: fixed to use the right path for {C,CPP,LD}FLAGS for openldap when cross-compiling

security/strongswan/strongswan.conf

@@ -36,9 +36,9 @@ fi
 # checking if we can enable CRL fetching using LDAP
 if pkginstalled openldap; then
 	pkgprefix -t openldap
-	var_append CFLAGS   ' ' "-I$( pkgprefix includedir openldap )"
-	var_append CPPFLAGS ' ' "-I$( pkgprefix includedir openldap )"
-	var_append LDFLAGS  ' ' "-L$( pkgprefix libdir openldap )"
+	var_append CFLAGS   ' ' "-I$( pkgprefix -r includedir openldap )"
+	var_append CPPFLAGS ' ' "-I$( pkgprefix -r includedir openldap )"
+	var_append LDFLAGS  ' ' "-L$( pkgprefix -r libdir openldap )"
 	export CPPFLAGS CFLAGS LDFLAGS
 
 	var_append extraconfopt ' ' "--enable-ldap"