[gtk+] build: Declare cairo_libs outside MSVC check block

[Emmanuele Bassi <ebassi src gnome org>]

commit 67d9cefb724bd88a444c4f44e460579e270b5817
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Fri Sep 15 15:57:34 2017 +0100

    build: Declare cairo_libs outside MSVC check block
    
    Otherwise there won't be a reference to it on non-MSVC builds.

 meson.build |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/meson.build b/meson.build
index 5051ec6..5056352 100644
--- a/meson.build
+++ b/meson.build
@@ -373,11 +373,11 @@ if cairogobj_dep.found()
   cairogobj_pkg_found = true
 endif
 
+cairo_libs = []
 if cc.get_id() == 'msvc'
   # Fallback depedency discovery for those on Visual Studio that do not generate
   # pkg-config files in their build systems for MSVC
   # Fallback for Cairo
-  cairo_libs = []
   if not cairo_dep.found()
     if (cc.has_header('cairo.h') and cc.has_header('cairo-win32.h'))
       cairo_dep = cc.find_library('cairo')