Fix typo in pkg_check_modules for GTK3. (#2534)

Author: j-jorge

core/CMakeLists.txt

@@ -588,7 +588,7 @@ if(LINUX)
 
     # including GTK3.0 and WebKit2Gtk4.x
     find_package(PkgConfig REQUIRED)
-    pkg_check_modules(GKT3 REQUIRED gtk+-3.0)
+    pkg_check_modules(GTK3 REQUIRED gtk+-3.0)
 
     set(_webkit2gtk_vers "4.1;4.0")
     foreach(_ver ${_webkit2gtk_vers})