Add a single unified OS detection header.

Author: insertinterestingnamehere

include/qt_os.h

@@ -0,0 +1,49 @@
+#ifndef QT_OS_H
+#define QT_OS_H
+
+// Not all Operating systems listed here are actually supported.
+
+#if defined(__linux__) || defined(QTHREADS_LINUX)
+#ifndef QTHREADS_LINUX
+#define QTHREADS_LINUX
+#endif
+
+#elif defined(__APPLE__) || defined(QTHREADS_APPLE)
+#ifndef QTHREADS_APPLE
+#define QTHREADS_APPLE
+#endif
+
+#elif defined(_WIN32) || defined(QTHREADS_WINDOWS)
+#ifndef QTHREADS_WINDOWS
+#define QTHREADS_WINDOWS
+#endif
+
+#elif defined(__FreeBSD__) || defined(QTHREADS_FREEBSD)
+#ifndef QTHREADS_FREEBSD
+#define QTHREADS_FREEBSD
+#endif
+
+#elif defined(__NetBSD__) || defined(QTHREADS_NETBSD)
+#ifndef QTHREADS_NETBSD
+#define QTHREADS_NETBSD
+#endif
+
+#elif defined(__OpenBSD__) || defined(QTHREADS_OPENBSD)
+#ifndef QTHREADS_OPENBSD
+#define QTHREADS_OPENBSD
+#endif
+
+#elif defined(__DragonFly__) || defined(QTHREADS_DRAGONFLYBSD)
+#ifndef QTHREADS_DRAGONFLYBSD
+#define QTHREADS_DRAGONFLYBSD
+#endif
+
+#elif defined(__sun)
+#error "Sun OS not currently supported."
+
+#else
+#error "Unrecognized OS"
+
+#endif
+
+#endif