[clutter] build: Use newer glib-genmarshal argument

[Emmanuele Bassi <ebassi src gnome org>]

commit 7d499a09e1ef7dae0f3e9be774f3be25e2aa76ff
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Tue Jul 11 11:32:18 2017 +0100

    build: Use newer glib-genmarshal argument
    
    When using glib-genmarshal from GLib 2.54, we can use the newly added
    `--prototypes` command line argument to generate the prototypes of the
    marshallers in the C source, and void a missing-prototypes compiler
    warning.

 build/autotools/Makefile.am.marshal |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/build/autotools/Makefile.am.marshal b/build/autotools/Makefile.am.marshal
index f29629c..3501ccf 100644
--- a/build/autotools/Makefile.am.marshal
+++ b/build/autotools/Makefile.am.marshal
@@ -34,6 +34,7 @@ stamp-marshal: $(marshal_list)
        $(AM_V_GEN)$(GLIB_GENMARSHAL) \
                --prefix=$(glib_marshal_prefix) \
                --header \
+               --valist-marshallers \
        $(marshal_list) > xgen-mh \
        && (cmp -s xgen-mh $(marshal_h) || cp -f xgen-mh $(marshal_h)) \
        && rm -f xgen-mh \
@@ -46,6 +47,8 @@ $(marshal_c): $(marshal_h)
        $(AM_V_GEN)$(GLIB_GENMARSHAL) \
                --prefix=$(glib_marshal_prefix) \
                --body \
+               --prototypes \
+               --valist-marshallers \
        $(marshal_list) > xgen-mc \
        && (cmp -s xgen-mc $(marshal_c) || cp -f xgen-mc $(marshal_c)) \
        && rm -f xgen-mc