slirp/slirp.h: Remove now-empty #ifdefs

After automatic cleanup to remove unnecessary #includes of headers that
osdep.h provides, slirp.h has a few now unnecessary #ifdef/#endif pairs;
remove them.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-id: 1456237112-32662-2-git-send-email-peter.maydell@linaro.org

slirp/slirp.h

@@ -24,28 +24,10 @@ typedef char *caddr_t;
 #endif
 
 
-#ifdef HAVE_UNISTD_H
-#endif
-
-#ifdef HAVE_STDLIB_H
-#endif
-
-
 #ifndef HAVE_MEMMOVE
 #define memmove(x, y, z) bcopy(y, x, z)
 #endif
 
-#if TIME_WITH_SYS_TIME
-#else
-# ifdef HAVE_SYS_TIME_H
-# else
-# endif
-#endif
-
-#ifdef HAVE_STRING_H
-#else
-#endif
-
 #ifndef _WIN32
 #include <sys/uio.h>
 #endif
@@ -96,12 +78,6 @@ void free(void *ptr);
 #include <ppp/slirppp.h>
 #endif
 
-#ifdef __STDC__
-#else
-#include <varargs.h>
-#endif
-
-
 /* Avoid conflicting with the libc insque() and remque(), which
    have different prototypes. */
 #define insque slirp_insque