cmake: Set process code page to UTF-8 on Windows

Additionally, this change adds app manifests to targets that were
previously missing them.

src/common/system.cpp

@@ -12,6 +12,7 @@
 #include <util/time.h>
 
 #ifdef WIN32
+#include <cassert>
 #include <codecvt>
 #include <compat/compat.h>
 #include <windows.h>
@@ -83,6 +84,7 @@ void SetupEnvironment()
         setenv("LC_ALL", "C.UTF-8", 1);
     }
 #elif defined(WIN32)
+    assert(GetACP() == CP_UTF8);
     // Set the default input/output charset is utf-8
     SetConsoleCP(CP_UTF8);
     SetConsoleOutputCP(CP_UTF8);