os: simplify win32 uname()

Just define struct utsname and a tiny uname() function instead of
cluttering the code with ifdef's.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1295>
(cherry picked from commit 77f9792911)

os/access.c

@@ -444,15 +444,7 @@ DefineSelf(int fd)
     caddr_t addr;
     int family;
     register HOST *host;
-
-#ifndef WIN32
     struct utsname name;
-#else
-    struct {
-        char nodename[512];
-    } name;
-#endif
-
     register struct hostent *hp;
 
     union {
@@ -478,11 +470,7 @@ DefineSelf(int fd)
      * uname() lets me access to the whole string (it smashes release, you
      * see), whereas gethostname() kindly truncates it for me.
      */
-#ifndef WIN32
     uname(&name);
-#else
-    gethostname(name.nodename, sizeof(name.nodename));
-#endif
 
     hp = _XGethostbyname(name.nodename, hparams);
     if (hp != NULL) {

os/osdep.h

@@ -206,4 +206,15 @@ extern void XdmcpRegisterBroadcastAddress(const struct sockaddr_in *addr);
 extern void XdmAuthenticationInit(const char *cookie, int cookie_length);
 #endif
 
+#ifdef WIN32
+#include <X11/Xwinsock.h>
+struct utsname {
+    char nodename[512];
+};
+
+static inline void uname(struct utsname *uts) {
+    gethostname(uts->nodename, sizeof(uts->nodename));
+}
+#endif /* WIN32 */
+
 #endif                          /* _OSDEP_H_ */