Need to define SVR4 on SVR4-ish systems since many headers and source files

check for it, expecting Imake to have defined it already. (Should be
    replaced with more specific checks & defines, but there's too many to
    get them all right now.)

configure.ac

@@ -599,6 +599,18 @@ else
 fi
 AC_DEFINE_UNQUOTED(X_BYTE_ORDER,[$ENDIAN],[Endian order])
 XORG_CFLAGS="$XORGSERVER_CFLAGS -DHAVE_XORG_CONFIG_H"
+
+# Imake defines SVR4 on SVR4 systems, and many files check for it, so
+# we need to replicate that here until those can all be fixed
+AC_MSG_CHECKING([if SVR4 needs to be defined])
+AC_EGREP_CPP([I_AM_SVR4],[
+#if defined(SVR4) || defined(__svr4__) || defined(__SVR4)
+ I_AM_SVR4
+#endif
+],[
+AC_DEFINE([SVR4],1,[Define to 1 on systems derived from System V Release 4])
+AC_MSG_RESULT([yes])], AC_MSG_RESULT([no]))
+
 test x$XORG = xyes && case $host_os in
   linux*)
   	XORG_OS="linux"

include/dix-config.h.in

@@ -257,6 +257,9 @@
 /* Define to 1 if you have the ANSI C header files. */
 #undef STDC_HEADERS
 
+/* Define to 1 on systems derived from System V Release 4 */
+#undef SVR4
+
 /* Support TCP socket connections */
 #undef TCPCONN
 

include/xorg-server.h.in

@@ -100,6 +100,9 @@
 /* Include time-based scheduler */
 #undef SMART_SCHEDULE
 
+/* Define to 1 on systems derived from System V Release 4 */
+#undef SVR4
+
 /* Support TCP socket connections */
 #undef TCPCONN