Prevent bug reports like #27260

ext/recode/config9.m4

@@ -0,0 +1,14 @@
+dnl
+dnl $Id$
+dnl
+
+dnl Check for extensions with which Recode can not work
+if test "$PHP_RECODE" != "no"; then
+  test "$PHP_IMAP"  != "no" && recode_conflict="$recode_conflict imap"
+  test "$PHP_MYSQL" != "no" && recode_conflict="$recode_conflict mysql"
+  test "$PHP_YAZ"   != "no" && recode_conflict="$recode_conflict yaz"
+
+  if test -n "$recode_conflict"; then
+    AC_MSG_ERROR([recode extension can not be configured together with:$recode_conflict])
+  fi
+fi