configure.in : Fix a dependency problem for "extra/" which shows up only in RPM builds.

configure.in:
  Some files in "extra/", notably "comp_err", depend on "dbug/libdbug.a",
  so "dbug/" must be a target before "extra/" is attempted.  Fix this.

configure.in

@@ -2516,9 +2516,9 @@ linked_client_targets="linked_libmysql_sources"
 
 if test "$THREAD_SAFE_CLIENT" = "no"
 then
-  sql_client_dirs="strings regex mysys extra libmysql client"
+  sql_client_dirs="strings regex mysys dbug extra libmysql client"
 else
-  sql_client_dirs="strings regex mysys extra libmysql libmysql_r client"
+  sql_client_dirs="strings regex mysys dbug extra libmysql libmysql_r client"
   linked_client_targets="$linked_client_targets linked_libmysql_r_sources"
   AC_CONFIG_FILES(libmysql_r/Makefile)
   AC_DEFINE([THREAD_SAFE_CLIENT], [1], [Should be client be thread safe])