[totem] build: Fix failure when not building a debug version

[Bastien Nocera <hadess src gnome org>]

commit 54e7c7f7e2a01b5d9fbcc4fe5b9b86ea4f16dfa3
Author: Jeremy Bicha <jbicha ubuntu com>
Date:   Thu Aug 10 00:05:28 2017 -0400

    build: Fix failure when not building a debug version
    
    Meson encountered an error in file src/backend/meson.build, line 90, column 0:
    Unknown variable "warn_flags".
    
    The warn_flags would not be initialised when the build was not a
    debug build. Initialise the variable outside the debug conditional.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=786083

 meson.build |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/meson.build b/meson.build
index 69cd2a1..a93d821 100644
--- a/meson.build
+++ b/meson.build
@@ -105,6 +105,8 @@ common_flags = [
   '-DLIBSOUP_DISABLE_SINGLE_INCLUDES'
 ]
 
+warn_flags = []
+
 if totem_buildtype == 'debug' or totem_buildtype == 'debugoptimized'
   test_cflags = [
     '-fno-strict-aliasing',
@@ -132,8 +134,6 @@ if totem_buildtype == 'debug' or totem_buildtype == 'debugoptimized'
     '-Wstrict-prototypes'
   ]
 
-  warn_flags = []
-
   foreach cflag: test_cflags
     if cc.has_argument(cflag)
       warn_flags += [cflag]