move windows.h include into its own header (to define LEAN_AND_MEAN and NOMINMAX in all places)

ostd/filesystem.hh

@@ -7,12 +7,9 @@
 #define OSTD_FILESYSTEM_HH
 
 #include "ostd/platform.hh"
+#include "ostd/internal/win32.hh"
 
-#ifdef OSTD_PLATFORM_WIN32
-#define WIN32_LEAN_AND_MEAN
-#define NOMINMAX
-#include <windows.h>
-#else
+#ifdef OSTD_PLATFORM_POSIX
 #include <unistd.h>
 #include <dirent.h>
 #include <sys/stat.h>

ostd/internal/win32.hh

@@ -0,0 +1,17 @@
+/* Windows includes.
+ *
+ * This file is part of OctaSTD. See COPYING.md for futher information.
+ */
+
+#ifndef OSTD_INTERNAL_WIN32_HH
+#define OSTD_INTERNAL_WIN32_HH
+
+#include "ostd/platform.hh"
+
+#ifdef OSTD_PLATFORM_WIN32
+#define WIN32_LEAN_AND_MEAN
+#define NOMINMAX
+#include <windows.h>
+#endif
+
+#endif

ostd/thread.hh

@@ -9,16 +9,14 @@
 #include <stdlib.h>
 #include <pthread.h>
 
-#ifndef OSTD_PLATFORM_WIN32
+#include "ostd/platform.hh"
+#include "ostd/internal/win32.hh"
+
+#ifdef OSTD_PLATFORM_POSIX
 #include <unistd.h>
-#else
-#define WIN32_LEAN_AND_MEAN
-#define NOMINMAX
-#include <windows.h>
 #endif
 
 #include "ostd/memory.hh"
-#include "ostd/platform.hh"
 #include "ostd/type_traits.hh"
 #include "ostd/tuple.hh"