win32/WinEvent: un-inline the constructor

Reduce header dependencies.

src/win32/WinEvent.cxx

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2020-2021 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "WinEvent.hxx"
+#include "system/Error.hxx"
+
+WinEvent::WinEvent()
+	:event(CreateEventW(nullptr, false, false, nullptr))
+{
+	if (!event)
+		throw FormatLastError("Error creating events");
+}

src/win32/WinEvent.hxx

@@ -20,7 +20,6 @@
 #ifndef MPD_WIN32_WINEVENT_HXX
 #define MPD_WIN32_WINEVENT_HXX
 
-#include "system/Error.hxx"
 #include <windows.h>
 
 // RAII for Windows unnamed event object
@@ -28,11 +27,11 @@
 
 class WinEvent {
 public:
-	WinEvent() : event(CreateEventW(nullptr, false, false, nullptr)) {
-		if (!event) {
-			throw FormatLastError("Error creating events");
-		}
-	}
+	/**
+	 * Throws on error.
+	 */
+	WinEvent();
+
 	~WinEvent() noexcept { CloseHandle(event); }
 	WinEvent(WinEvent &&) = delete;
 	WinEvent(const WinEvent &) = delete;

src/win32/meson.build

@@ -7,6 +7,7 @@ win32 = static_library(
   'win32',
   'ComWorker.cxx',
   'HResult.cxx',
+  'WinEvent.cxx',
   include_directories: inc,
 )