[shotwell] i18n: Add C_ to vala keywords

[Jens Georg <jensgeorg src gnome org>]

commit 1eb0bda52970a86e751cb1789d1205f350538c65
Author: Jens Georg <mail jensge org>
Date:   Sun Jul 10 14:47:49 2016 +0200

    i18n: Add C_ to vala keywords
    
    Signed-off-by: Jens Georg <mail jensge org>
    
    https://bugzilla.gnome.org/show_bug.cgi?id=744255

 po/Makevars |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/po/Makevars b/po/Makevars
index 42d9809..2ea0037 100644
--- a/po/Makevars
+++ b/po/Makevars
@@ -8,7 +8,7 @@ subdir = po
 top_builddir = ..
 
 # These options get passed to xgettext.
-XGETTEXT_OPTIONS = --from-code=UTF-8
+XGETTEXT_OPTIONS = --from-code=UTF-8 --keyword=C_:1c,2
 
 # This is the copyright holder that gets inserted into the header of the
 # $(DOMAIN).pot file.  Set this to the copyright holder of the surrounding