pixma: Fix sane options file generation

This now generates files in the source tree and includes them in the
source tarball together with the script used.  Explicit dependencies
are added to trigger generation.  Rules have been rewritten to use
implicit variables for brevity.

backend/Makefile.am

@@ -56,14 +56,6 @@ dll-preload.h:
 	fi; \
 	echo "};" >> $@
 
-# generate options files for pixma backend
-pixma/pixma_sane_options.h:
-	@echo Generating pixma_sane_options.h from pixma.c
-	@python pixma/scripts/pixma_gen_options.py h < pixma/pixma.c > pixma/pixma_sane_options.h
-pixma/pixma_sane_options.c:
-	@echo Generating pixma_sane_options.c from pixma.c
-	@python pixma/scripts/pixma_gen_options.py < pixma/pixma.c > pixma/pixma_sane_options.c
-
 # TODO: This really belongs together with the saned sources and
 # should be installed there as well.
 EXTRA_DIST += saned.conf.in
@@ -945,15 +937,30 @@ libpixma_la_SOURCES = pixma/pixma.c \
 	pixma/pixma_rename.h
 libpixma_la_CPPFLAGS = $(AM_CPPFLAGS) $(XML_CFLAGS) -DBACKEND_NAME=pixma
 
+# Generate options files included by pixma/pixma.c from said file.
+# The circular dependency means we cannot add it as a prerequisite
+# for the targets that build the options files.
+
+$(srcdir)/pixma/pixma.c: \
+	$(srcdir)/pixma/pixma_sane_options.h \
+	$(srcdir)/pixma/pixma_sane_options.c
+
+$(srcdir)/pixma/pixma_sane_options.h:
+	@echo Generating $@ from $(@D)/pixma.c
+	@(cd $(@D); python scripts/pixma_gen_options.py h < pixma.c > $(@F))
+$(srcdir)/pixma/pixma_sane_options.c:
+	@echo Generating $@ from $(@D)/pixma.c
+	@(cd $(@D); python scripts/pixma_gen_options.py   < pixma.c > $(@F))
+
+EXTRA_DIST += pixma/pixma_sane_options.c
+EXTRA_DIST += pixma/pixma_sane_options.h
+EXTRA_DIST += pixma/scripts/pixma_gen_options.py
+
 nodist_libsane_pixma_la_SOURCES = pixma-s.c
 libsane_pixma_la_CPPFLAGS = $(AM_CPPFLAGS) -DBACKEND_NAME=pixma
 libsane_pixma_la_LDFLAGS = $(DIST_SANELIBS_LDFLAGS)
 libsane_pixma_la_LIBADD = $(COMMON_LIBS) libpixma.la ../sanei/sanei_init_debug.lo ../sanei/sanei_constrain_value.lo ../sanei/sanei_config.lo  sane_strstatus.lo ../sanei/sanei_usb.lo ../sanei/sanei_thread.lo $(SANEI_SANEI_JPEG_LO) $(JPEG_LIBS) $(XML_LIBS) $(MATH_LIB) $(SOCKET_LIBS) $(USB_LIBS) $(SANEI_THREAD_LIBS) $(RESMGR_LIBS)
 EXTRA_DIST += pixma.conf.in
-# included in pixma.c
-BUILT_SOURCES = pixma/pixma_sane_options.c pixma/pixma_sane_options.h
-CLEANFILES += pixma/pixma_sane_options.c pixma/pixma_sane_options.h
-
 
 libplustek_la_SOURCES = plustek.c plustek.h
 libplustek_la_CPPFLAGS = $(AM_CPPFLAGS) -DBACKEND_NAME=plustek
@@ -1223,7 +1230,7 @@ libdll_preload_la_LIBADD = ../sanei/sanei_usb.lo $(USB_LIBS) $(XML_LIBS)
 libdll_la_SOURCES =  dll.c
 libdll_la_CPPFLAGS = $(AM_CPPFLAGS) -DBACKEND_NAME=dll
 libdll_la_LIBADD = ../sanei/sanei_usb.lo $(USB_LIBS) $(XML_LIBS)
-BUILT_SOURCES += dll-preload.h
+BUILT_SOURCES = dll-preload.h
 CLEANFILES += dll-preload.h
 
 nodist_libsane_dll_la_SOURCES =  dll-s.c