--- src/mkfiles/makefile.all
+++ src/mkfiles/makefile.all
@@ -296,7 +296,7 @@
 OBJDIR = gw32objs# Location of objects
 TGTBASE=$(OBJDIR)/libslang
 prefix=/mingw/local
-module_install_dir = $(prefix)/lib/slang/v2/modules#
+module_install_dir = $(FREETZ_LIBRARY_DIR)/slang#
 install_doc_dir = $(prefix)/share/doc/slang/v2
 slstd_C_FLAGS = -DSLANG_DOC_DIR='"$(install_doc_dir)"' -DSLANG_INSTALL_PREFIX='"$(prefix)"'
 slimport_C_FLAGS = -DMODULE_INSTALL_DIR='"$(module_install_dir)"'
--- src/slimport.c
+++ src/slimport.c
@@ -53,7 +53,7 @@
 # define MODULE_PATH_ENV_NAME "SLANG_MODULE_PATH"
 #endif
 #ifndef MODULE_INSTALL_DIR
-# define MODULE_INSTALL_DIR "/usr/local/lib/slang/v2/modules"
+# error "Freetz: MODULE_INSTALL_DIR is expected to be set externally, see module_install_dir.patch for details."
 #endif
 
 #define MAX_MODULE_NAME_SIZE 256