[gtk+] build: Use correct compiler flag

[Emmanuele Bassi <ebassi src gnome org>]

commit 7b73bc35722ffe0f49ec2850e23073828a329fc3
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Mon Oct 17 15:12:21 2016 +0100

    build: Use correct compiler flag
    
    The name is -Wformat-nonliteral.

 configure.ac |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 3ce9c31..b915438 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1880,7 +1880,7 @@ AS_IF([test "x$enable_compile_warnings" = xyes], [
     -Wmissing-include-dirs dnl
     -Wshadow dnl
     -Wformat=2 dnl
-    -Wformat-non-literal dnl
+    -Wformat-nonliteral dnl
     -Wformat-security dnl
     -Wimplicit-function-declaration dnl
     -Werror=redundant-decls dnl