[yelp] Fix deprecated way of calling glib-genmarshal

[Shaun McCance <shaunm src gnome org>]

commit de92c2e9577b63f9d28e114c62d3e1a6dd6a8878
Author: Shaun McCance <shaunm gnome org>
Date:   Sun Jun 6 12:45:16 2021 -0400

    Fix deprecated way of calling glib-genmarshal

 Makefile.am | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/Makefile.am b/Makefile.am
index 1cc30ae3..4551da42 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -97,7 +97,7 @@ libyelp/yelp-marshal.h: libyelp/yelp-marshal.list
        $(AM_V_GEN)$(GLIB_GENMARSHAL) --prefix=yelp_marshal --header --internal $< > $@
 
 libyelp/yelp-marshal.c: libyelp/yelp-marshal.list libyelp/yelp-marshal.h
-       $(AM_V_GEN)$(GLIB_GENMARSHAL) --prefix=yelp_marshal --header --body --internal $< > $@
+       $(AM_V_GEN)$(GLIB_GENMARSHAL) --prefix=yelp_marshal --body --prototypes --internal $< > $@
 
 enum_data = \
        libyelp/yelp-types.c \