autotools: GNU sort isn't required, we just need the -V option to be …

…supported.

configure

@@ -13521,7 +13521,8 @@ test -n "$SORT" || SORT="false"
 
 if ! "$SORT" -V </dev/null >/dev/null
 then :
-  as_fn_error $? "GNU sort(1) is required" "$LINENO" 5
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: sort(1) that supports the -V option is required to find dynamic libraries" >&5
+printf "%s\n" "$as_me: WARNING: sort(1) that supports the -V option is required to find dynamic libraries" >&2;}
 fi
 
 case "$host" in

configure.ac

@@ -75,7 +75,7 @@ if [ test -z "$AWK" ]; then
 fi
 
 AC_CHECK_PROGS([SORT], [gsort sort], [false])
-AS_IF([! "$SORT" -V </dev/null >/dev/null], [AC_MSG_ERROR([GNU sort(1) is required])])
+AS_IF([! "$SORT" -V </dev/null >/dev/null], [AC_MSG_WARN([sort(1) that supports the -V option is required to find dynamic libraries])])
 
 case "$host" in
     *-*-beos*)