[libmediaart] build: Improve dependency tracking for marshallers sources

[Emmanuele Bassi <ebassi src gnome org>]

commit dc757b7a68169f4093467f00ca4da5afba9ba041
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Mon Jul 17 13:14:28 2017 +0100

    build: Improve dependency tracking for marshallers sources
    
    Under massive parallelism — like the Continuous build — we may end up in
    a situation where the sources get built before the marshaller sources
    are generated.
    
    Let's try to increase chances that the dependency tracking inside
    Automake will do the right thing.

 libmediaart/Makefile.am |   14 ++++++++------
 1 files changed, 8 insertions(+), 6 deletions(-)
---
diff --git a/libmediaart/Makefile.am b/libmediaart/Makefile.am
index 9d94c7a..0e55b6a 100644
--- a/libmediaart/Makefile.am
+++ b/libmediaart/Makefile.am
@@ -10,6 +10,10 @@ lib_LTLIBRARIES = libmediaart-@LIBMEDIAART_API_VERSION@.la
 libmediaartdir = $(libdir)/libmediaart-$(LIBMEDIAART_API_VERSION)/
 libmediaartincludedir=$(includedir)/libmediaart-$(LIBMEDIAART_API_VERSION)/libmediaart/
 
+libmediaart_marshal_sources = \
+       marshal.c \
+       marshal.h
+
 libmediaart_sources = \
        cache.c \
        cache.h \
@@ -26,9 +30,8 @@ libmediaartinclude_HEADERS = \
        extractgeneric.h
 
 libmediaart_@LIBMEDIAART_API_VERSION@_la_SOURCES = \
-       $(libmediaart_sources) \
-       marshal.c \
-       marshal.h
+       $(libmediaart_marshal_sources) \
+       $(libmediaart_sources)
 
 if HAVE_GDKPIXBUF
 libmediaart_@LIBMEDIAART_API_VERSION@_la_SOURCES += extractpixbuf.c
@@ -55,14 +58,13 @@ libmediaart_@LIBMEDIAART_API_VERSION@_la_LIBADD = \
 marshal.h: marshal.list
        $(AM_V_GEN)$(GLIB_GENMARSHAL) $< --prefix=media_art_marshal --header > $@
 
-marshal.c: marshal.list
+marshal.c: marshal.list marshal.h
        $(AM_V_GEN)(echo "#include \"marshal.h\""; \
            $(GLIB_GENMARSHAL) $< --prefix=media_art_marshal --body) > $@
 
 
 BUILT_SOURCES = \
-       marshal.c \
-       marshal.h
+       $(libmediaart_marshal_sources)
 
 CLEANFILES = $(BUILT_SOURCES)