[directwrite] Link to library

Instead of loading at runtime. I just want to see how CI deals with
this. Otherwise, not depending on dwrite is probably desired.

meson.build

@@ -332,12 +332,16 @@ if host_machine.system() == 'windows' and not get_option('gdi').disabled()
   endif
 endif
 
+directwrite_dep = []
 # DirectWrite (Windows)
 if host_machine.system() == 'windows' and not get_option('directwrite').disabled()
   if get_option('directwrite').enabled() and not cpp.has_header('dwrite_3.h')
     error('DirectWrite was enabled explicitly, but required header is missing.')
   endif
-  conf.set('HAVE_DIRECTWRITE', 1)
+  directwrite_dep = cpp.find_library('dwrite', required: get_option('directwrite'))
+  if directwrite_dep.found()
+    conf.set('HAVE_DIRECTWRITE', 1)
+  endif
 endif
 
 # CoreText (macOS)

src/hb-directwrite.hh

@@ -188,25 +188,8 @@ struct hb_directwrite_global_t
 {
   hb_directwrite_global_t ()
   {
-    dwrite_dll = LoadLibraryW (L"DWrite.dll");
+    HRESULT hr = DWriteCreateFactory (DWRITE_FACTORY_TYPE_SHARED, __uuidof (IDWriteFactory),
-
+				      (IUnknown**) &dwriteFactory);
-#if defined(__GNUC__) || defined(__clang__)
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wcast-function-type"
-#endif
-
-    t_DWriteCreateFactory p_DWriteCreateFactory = (t_DWriteCreateFactory)
-			    GetProcAddress (dwrite_dll, "DWriteCreateFactory");
-
-#if defined(__GNUC__) || defined(__clang__)
-#pragma GCC diagnostic pop
-#endif
-
-    if (unlikely (!p_DWriteCreateFactory))
-      return;
-
-    HRESULT hr = p_DWriteCreateFactory (DWRITE_FACTORY_TYPE_SHARED, __uuidof (IDWriteFactory),
-					(IUnknown**) &dwriteFactory);
 
     if (unlikely (hr != S_OK))
       return;
@@ -222,12 +205,9 @@ struct hb_directwrite_global_t
       fontFileLoader->Release ();
     if (dwriteFactory)
       dwriteFactory->Release ();
-    if (dwrite_dll)
-      FreeLibrary (dwrite_dll);
   }
 
   bool success = false;
-  HMODULE dwrite_dll;
   IDWriteFactory *dwriteFactory;
   DWriteFontFileLoader *fontFileLoader;
 };

src/meson.build

@@ -513,6 +513,7 @@ endif
 if conf.get('HAVE_DIRECTWRITE', 0) == 1
   hb_sources += hb_directwrite_sources
   hb_headers += hb_directwrite_headers
+  harfbuzz_deps += directwrite_dep
   # hb-directwrite needs a C++ linker
   libharfbuzz_link_language = 'cpp'
 endif