when we disable the bundled libs, make sure we don't try to run install in them

--- converter/other/jbig/Makefile
+++ converter/other/jbig/Makefile
@@ -5,7 +5,7 @@ endif
 SUBDIR = converter/other/jbig
 VPATH=.:$(SRCDIR)/$(SUBDIR)
 
-SUBDIRS = libjbig
+SUBDIRS =
 
 include $(BUILDDIR)/config.mk
 
@@ -35,6 +35,7 @@ SCRIPTS =
 
 ifeq ($(JBIGLIB),$(INTERNAL_JBIGLIB))
   JBIGLIB_DEP = $(JBIGLIB)
+  SUBDIRS += libjbig
 else
   # It's not our internal version; user's on his own to make sure it's built
 endif
--- converter/other/jpeg2000/Makefile
+++ converter/other/jpeg2000/Makefile
@@ -5,7 +5,7 @@ endif
 SUBDIR = converter/other/jpeg2000
 VPATH=.:$(SRCDIR)/$(SUBDIR)
 
-SUBDIRS = libjasper
+SUBDIRS =
 
 include $(BUILDDIR)/config.mk
 
@@ -52,6 +52,7 @@ ifeq ($(JASPERLIB),$(INTERNAL_JASPERLIB)
   # MERGE_OBJECTS contains relative paths, so $(INTERNAL_JASPERLIB) had better
   # be relative to the current directory.
   MERGE_OBJECTS += $(JASPERLIB)
+  SUBDIRS += libjasper
 endif
 MERGEBINARIES = $(BINARIES)