Install header include/ddd.h

[[Imported from SVN: r8490]]

parallel/ddd/Makefile.am

@@ -49,6 +49,8 @@ MISC = analyser/inv.c
 DDD = ddd.c dddi.h
 
 # header files that are not explicitly used but need to be distributed
+pgkinclude_HEADERS = include/ddd.h
+
 EXTRA_DIST = include/dddaddon.h include/ddd.h include/memmgr.h include/dddio.h \
              include/fddd.f include/dddresources.h join/join.h ctrl/stat.h \
              xfer/xfer.h xfer/sll.ct xfer/sll.h xfer/sll.ht if/if.h if/ifstd.ct if/ifcmd.ct \