[gtk+] build: Fix the non-pkg-config Vulkan detection

[Emmanuele Bassi <ebassi src gnome org>]

commit 00990ec3072bfe6be20117e973adb123fc3c36ee
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Mon Feb 5 14:35:34 2018 +0000

    build: Fix the non-pkg-config Vulkan detection
    
    Not all the variables were renamed.

 meson.build |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/meson.build b/meson.build
index d7e7a72..3c7972d 100644
--- a/meson.build
+++ b/meson.build
@@ -568,7 +568,7 @@ else
       vulkan_libname = 'vulkan'
     endif
     vulkan_dep = cc.find_library(vulkan_libname, required: false)
-    if vulkan_lib.found() and cc.has_function('vkCreateInstance', dependencies: vulkan_lib) and 
cc.has_header('vulkan/vulkan.h')
+    if vulkan_dep.found() and cc.has_function('vkCreateInstance', dependencies: vulkan_dep) and 
cc.has_header('vulkan/vulkan.h')
       have_vulkan = true
       pc_gdk_extra_libs += ['-l@0@'.format(vulkan_libname)]
     endif