diff --git a/config.project b/config.project
index de383e9..80669df 100644
--- a/config.project
+++ b/config.project
@@ -12,7 +12,7 @@ mb_disable_static=no
 mb_disable_shared=no
 
 # custom config step
-mb_use_custom_cfgdefs=no
+mb_use_custom_cfgdefs=yes
 mb_use_custom_cfgtest=no
 
 # pkgconfig
diff --git a/project/config/cfgdefs.in b/project/config/cfgdefs.in
new file mode 100644
index 0000000..191a7e7
--- /dev/null
+++ b/project/config/cfgdefs.in
@@ -0,0 +1,2 @@
+# optionally install libsltdl (also) as a libltdl drop-in replacement?
+LTDL_DROP_IN_REPLACEMENT = @ltdl_drop_in_replacement@
diff --git a/project/config/cfgdefs.sh b/project/config/cfgdefs.sh
new file mode 100644
index 0000000..ac597c9
--- /dev/null
+++ b/project/config/cfgdefs.sh
@@ -0,0 +1,42 @@
+# in projects where [ $mb_use_custom_cfgdefs = yes ],
+# cfgdefs.sh is invoked from within ./configure via
+# . $mb_project_dir/project/cfgdefs.sh
+
+# a successful return from cfgdefs.sh will be followed
+# by a second invocation of the config_copy() function,
+# reflecting any changes to common config variables
+# made by cfgdefs.sh.
+
+# finally, cfgdefs.sh may update the contents of the
+# config-time generated cfgdefs.mk.
+
+
+ltdl_drop_in_replacement='no'
+
+for arg ; do
+	case "$arg" in
+		--as-ltdl-drop-in-replacement )
+			ltdl_drop_in_replacement='yes' ;;
+
+		*)
+			error_msg ${arg#}: "unsupported config argument."
+			exit 2
+	esac
+done
+
+
+cfgdefs_output_custom_defs()
+{
+	sed \
+		-e 's/@ltdl_drop_in_replacement@/'"$ltdl_drop_in_replacement"'/g' \
+		"$mb_project_dir/project/config/cfgdefs.in"                       \
+	| sed -e 's/[ \t]*$//g'                                                   \
+			>> "$mb_pwd/cfgdefs.mk"
+}
+
+
+# cfgdefs.in --> cfgdefs.mk
+cfgdefs_output_custom_defs
+
+# all done
+return 0
diff --git a/project/config/cfgdefs.usage b/project/config/cfgdefs.usage
new file mode 100644
index 0000000..b9fca0e
--- /dev/null
+++ b/project/config/cfgdefs.usage
@@ -0,0 +1,6 @@
+configure: libsltdl specific switches:
+--------------------------------------
+	--as-ltdl-drop-in-replacement   install additional symlinks that
+                                         would allow using libsltdl as a
+                                         drop-in replacement of the legacy
+                                         ltdl library.
diff --git a/project/extras.mk b/project/extras.mk
index e69de29..5aa769b 100644
--- a/project/extras.mk
+++ b/project/extras.mk
@@ -0,0 +1,37 @@
+ifeq ($(LTDL_DROP_IN_REPLACEMENT),yes)
+
+LIBLTDL_SOLINK = $(OS_LIB_PREFIX)ltdl$(OS_LIB_SUFFIX)
+LIBLTDL_ARLINK = $(OS_LIB_PREFIX)ltdl$(OS_ARCHIVE_EXT)
+LIBLTDL_IMPLIB = $(OS_LIB_PREFIX)ltdl$(OS_IMPLIB_EXT)
+
+install-headers-ltdl:
+	mkdir -p $(DESTDIR)$(INCLUDEDIR)
+	rm -f $(DESTDIR)$(INCLUDEDIR)/ltdl.h.tmp
+	ln -s sltdl/sltdl.h $(DESTDIR)$(INCLUDEDIR)/ltdl.h.tmp
+	mv $(DESTDIR)$(INCLUDEDIR)/ltdl.h.tmp $(DESTDIR)$(INCLUDEDIR)/ltdl.h
+
+install-shared-ltdl:
+	rm -f lib/libltdl.so.tmp
+	ln -s $(DSO_SOLINK) lib/libltdl.so.tmp
+	mv lib/libltdl.so.tmp $(DESTDIR)$(LIBDIR)/$(LIBLTDL_SOLINK)
+
+install-static-ltdl:
+	rm -f lib/libltdl.a.tmp
+	ln -s $(STATIC_LIB_NAME) lib/libltdl.a.tmp
+	mv lib/libltdl.a.tmp $(DESTDIR)$(LIBDIR)/$(LIBLTDL_ARLINK)
+
+install-implib-ltdl:
+	rm -f lib/libltdl.lib.a.tmp
+	ln -s $(IMP_SOLINK) lib/libltdl.lib.a.tmp
+	mv lib/libltdl.lib.a.tmp $(DESTDIR)$(LIBDIR)/$(LIBLTDL_IMPLIB)
+
+
+install-headers:    install-headers-ltdl
+install-static:     install-static-ltdl
+install-shared:     install-shared-ltdl
+
+ifeq ($(CC_BINFMT),PE)
+install-shared:     install-implib-ltdl
+endif
+
+endif