[gmime] Fixed Vala binding build

[Rico Tzschichholz <ricotz src gnome org>]

commit 406fe0a4997cdcbd8092146f4e13a9adc044fe11
Author: Jeffrey Stedfast <jestedfa microsoft com>
Date:   Sat Feb 15 11:15:32 2020 -0500

    Fixed Vala binding build

 gmime/Makefile.am | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/gmime/Makefile.am b/gmime/Makefile.am
index 35ade9db..afbb14dd 100644
--- a/gmime/Makefile.am
+++ b/gmime/Makefile.am
@@ -230,7 +230,7 @@ gmime-3.0.vapi: GMime-3.0.gir GMime-3.0.metadata GMime-3.0-custom.vala
 VAPIGEN_VAPIS = gmime-3.0.vapi
 gmime_3_0_vapi_DEPS = gio-2.0
 gmime_3_0_vapi_METADATADIRS = $(srcdir)
-gmime_3_0_vapi_FILES = GMime-3.0.gir GMime-3.0-custom.vala
+gmime_3_0_vapi_FILES = GMime-3.0.gir $(srcdir)/GMime-3.0-custom.vala
 
 gmime-3.0.deps:
        $(AM_V_GEN) for pkg in $(gmime_3_0_vapi_DEPS); do \
@@ -240,6 +240,6 @@ gmime-3.0.deps:
 vapidir = $(datadir)/vala/vapi
 vapi_DATA = $(VAPIGEN_VAPIS) $(VAPIGEN_VAPIS:.vapi=.deps)
 
-EXTRA_DIST += GMime-3.0.metadata
+EXTRA_DIST += GMime-3.0.metadata GMime-3.0-custom.vala
 CLEANFILES += $(vapi_DATA)
 endif