File libdwarf-fix-parallel-build.diff of Package libdwarf

Fix parallel libdwarf build

As we build libdwarf in parallel (which upstream doesn't),
it can happen that gennames is called twice in parallel (for
dwarf_names.c and dwarf_names.h), overwriting each others output,
resulting in shortened generated files (ultimately resulting in compile
errors).  This patch makes sure it's only called once.

--- libdwarf/Makefile.in.orig	2015-01-21 14:33:26.000000000 +0100
+++ libdwarf/Makefile.in	2015-01-21 14:34:35.000000000 +0100
@@ -142,7 +142,8 @@ common.o: $(srcdir)/common.c $(srcdir)/c
 	$(CC) $(CFLAGS) -c $(srcdir)/common.c
 gennames: $(srcdir)/gennames.c $(srcdir)/dwarf.h common.o
 	$(CC) $(CFLAGS) $(srcdir)/gennames.c common.o $(LDFLAGS) -o gennames
-dwarf_names.c dwarf_names.h: gennames $(srcdir)/dwarf.h
+dwarf_names.h: dwarf_names.c
+dwarf_names.c: gennames $(srcdir)/dwarf.h
 	rm -f dwarf_names.h dwarf_names.c
 	./gennames  @dwarf_namestable@  -i $(srcdir) -o .