diff --git a/ChangeLog b/ChangeLog
index 6ea9b615c..e10c7a330 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2001-05-26  Pavel Roskin  <proski@gnu.org>
+
+	* configure.in: Define SCO_FLAVOR based on $host_os, not on the
+	user choice.
+	* acconfig.h: Changes for the above.
+	* INSTALL: Don't document --with-sco - it's now defunct.
+	* INSTALL.FAST: Likewise.
+
 2001-05-25  Pavel Roskin  <proski@gnu.org>
 
 	* lib/mc.ext.in: Match both "mail" and "Mail", but only if they
diff --git a/INSTALL b/INSTALL
index 708c2d57a..185a8487b 100644
--- a/INSTALL
+++ b/INSTALL
@@ -118,12 +118,6 @@ installed the gpm package.
 `--with-mmap'
      Needed when compiling under AIX if you want the fast viewer.
 
-`--with-sco'
-     This option is used to compile on SCO: it turns on SCO-specific
-     code, i.e. disables the terminal resizing mechanism, uses the
-     BSD-like pseudoterminal handling, adds screen-saving capabilities
-     on console, etc.
-
 `--with-subshell[=optional]', `--without-subshell' 
      The subshell support is by default turned on, you can disable
      this by using the --without-subshell option.  If you pass the
diff --git a/INSTALL.FAST b/INSTALL.FAST
index 1bb3453e6..4f8e8fba5 100644
--- a/INSTALL.FAST
+++ b/INSTALL.FAST
@@ -46,9 +46,6 @@ replacement for SysV curses).
 	The configure will append `lib' and `include' to find the libgpm.a
 	and gpm.h files respectively.
 
-`--with-sco'
-	If you are compiling on a SCO machine.
-
    You may also want to specify CFLAGS for the compiler, even if it finds
    itself some defaults by typing e.g.
 
diff --git a/acconfig.h b/acconfig.h
index 079d4ae02..0cbe3ec4b 100644
--- a/acconfig.h
+++ b/acconfig.h
@@ -145,9 +145,6 @@
 /* Defined if your CPP understands ## macro token pasting method */
 #undef HAVE_PORTABLE_TOKEN_PASTING
 
-/* Define if you want to turn on SCO-specific code */
-#undef SCO_FLAVOR
-
 /* Define if your system has struct linger */
 #undef HAVE_STRUCT_LINGER
 
diff --git a/configure.in b/configure.in
index 639adb95f..0d3ce76e2 100644
--- a/configure.in
+++ b/configure.in
@@ -66,14 +66,20 @@ AM_PATH_GLIB(1.2.0,,[AC_MSG_ERROR([Test for GLIB failed.  MC requires GLIB.])])
 LIBS="$LIBS $GLIB_LIBS"
 
 dnl
-dnl For A/UX.  Do not move
+dnl OS specific flags.
 dnl
 
 posix_libs=""
 case $host_os in
 aux*)
+    # A/UX
     posix_libs="-lposix"
     AC_DEFINE(_POSIX_SOURCE)
+    ;;
+sco*)
+    AC_DEFINE(SCO_FLAVOR, 1, [Define if you want to turn on SCO-specific code])
+    AC_DEFINE(_SVID3, 1, [Needs to be defined on SCO])
+    ;;
 esac
 
 AC_PROG_INSTALL
@@ -340,14 +346,6 @@ dnl	AC_MSG_WARN([display/input problems.])
 dnl	AC_MSG_WARN([Reconsider using xcurses])
 dnl])
 
-AC_ARG_WITH(sco,
-	[--with-sco                 Use this to turn on SCO-specific code],[
-	if test x$withval = xyes; then
-		AC_DEFINE(SCO_FLAVOR)
-		CFLAGS="$CFLAGS -D_SVID3"
-	fi
-])
-
 AC_ARG_WITH(sunos-curses,
 	[--with-sunos-curses        Used to force SunOS 4.x curses],[
 	if test x$withval = xyes; then