fix for fails to build with parallel make

Signed-of-by: Joerg Bornkessel <hd_brummy@gentoo.org> (02 Feb 2011)
diff -Naur burn-0.2.0-beta5.orig/Makefile burn-0.2.0-beta5/Makefile
--- burn-0.2.0-beta5.orig/Makefile	2011-02-02 01:32:42.000000000 +0100
+++ burn-0.2.0-beta5/Makefile	2011-02-02 01:34:20.000000000 +0100
@@ -9,6 +9,9 @@
 #
 PLUGIN = burn
 
+# Enable DMH Archive
+#ENABLE_DMH_ARCHIVE = 1
+
 ### The version number of this plugin (taken from the main source file):
 
 VERSION = $(shell grep 'const char\* plugin::VERSION *=' $(PLUGIN).c | awk '{ print $$5 }' | sed -e 's/[";]//g')
@@ -144,7 +147,7 @@
 
 SUBDIRS:
 	@for dir in $(SUBDIRS); do \
-		make -C $$dir CXX="$(CXX)" CXXFLAGS="$(CXXFLAGS)" lib$$dir.a ; \
+		$(MAKE) -C $$dir CXX="$(CXX)" CXXFLAGS="$(CXXFLAGS)" lib$$dir.a ; \
 	done
 
 libvdr-$(PLUGIN).so: $(OBJS) SUBDIRS Makefile
@@ -176,7 +179,7 @@
 	@-rm -f *.o genindex/*.o $(DEPFILE) *.so *.tgz core* *~ burn-buffers \
 		scan-test test t/*.o
 	@for dir in $(SUBDIRS); do \
-		make -C $$dir clean ; \
+		$(MAKE) -C $$dir clean ; \
 	done
 
 ### Implicit rules: