Some systems (HP-UX) don't yet have <sys/select.h>, putting select() in

<sys/time.h>.  Cope with this.  Where <sys/select.h> _is_ available, though,
use it (since it's where POSIX puts select()).  Problem reported by Mike
Protts.

[originally from svn r6310]

unix/configure.ac

@@ -14,7 +14,7 @@ if test "X$GCC" = Xyes; then
     CFLAGS="$CFLAGS -Wall -Werror"
 fi
 
-AC_CHECK_HEADERS([utmpx.h],,,[
+AC_CHECK_HEADERS([utmpx.h sys/select.h],,,[
 #include <sys/types.h>
 #include <utmp.h>])
 
@@ -45,4 +45,7 @@ AH_BOTTOM([
 #ifndef HAVE_PTSNAME
 # define BSD_PTYS
 #endif
+#ifndef HAVE_SYS_SELECT_H
+# define HAVE_NO_SYS_SELECT_H
+#endif
 ])