Enable automated build and install runs on FreeBSD for ODE.

ODE does not build on FreeBSD out of the box, so an automated patchfile
is included as well.
The 'clean' target reverses the patches that were done by 'all'.

extern/Makefile

@@ -30,13 +30,17 @@
 # ***** END GPL/BL DUAL LICENSE BLOCK *****
 # Bounces make to subdirectories. Also installs after succesful all target.
 
+include nan_definitions.mk
+
 SOURCEDIR = extern
+DIR = $(OCGDIR)/extern
+DIRS = ode
 
-ALLDIRS = ode
+include nan_subdirs.mk
 
-all::
-	@for i in $(ALLDIRS); do \
+install:
+	@for i in $(DIRS); do \
 	    echo "====> $(MAKE) $@ in $(SOURCEDIR)/$$i" ;\
-	    $(MAKE) -C $$i install || exit 1; \
+	    $(MAKE) -C $$i $@ || exit 1; \
 	done