mysql55 - using builtin readline breaks building

[BjarneDMat]

r93312

--->  Installing mysql55 à5.5.24_2+system_readline
The mysql55 client has been installed.
To install the mysql55 server, install the mysql55-server port.
--->  Activating mysql55 à5.5.24_2+system_readline
--->  Cleaning mysql55
--->  Updating database of binaries: 100.0%
--->  Scanning binaries for linking errors: 100.0%
--->  No broken files found.
pro17:MacPorts root# port -n -f upgrade --force --enforce-variants mysql55 -system_readline
--->  Computing dependencies for mysql55
--->  Fetching distfiles for mysql55
--->  Verifying checksum(s) for mysql55
--->  Extracting mysql55
--->  Applying patches to mysql55
--->  Configuring mysql55
--->  Building mysql55
Error: org.macports.build for port mysql55 returned: command execution failed
Please see the log file for port mysql55 for details:
    /macports/var/macports/logs/_macports_var_macports_sources_rsync.macports.org_release_tarballs_ports_databases_mysql55/mysql55/main.log
Error: Unable to upgrade port: 1

[ 71%] Built target mysql_client_test
make[1]: Leaving directory `/macports/var/macports/build/_macports_var_macports_sources_rsync.macports.org_release_tarballs_ports_databases_mysql55/mysql55/work/mysql-5.5.24'
make: *** [all] Error 2
make: Leaving directory `/macports/var/macports/build/_macports_var_macports_sources_rsync.macports.org_release_tarballs_ports_databases_mysql55/mysql55/work/mysql-5.5.24'
Command failed:  cd "/macports/var/macports/build/_macports_var_macports_sources_rsync.macports.org_release_tarballs_ports_databases_mysql55/mysql55/work/mysql-5.5.24" && /usr/bin/make -j8 -w all 
Exit code: 2
Error: org.macports.build for port mysql55 returned: command execution failed
DEBUG: Error code: CHILDSTATUS 59063 2
DEBUG: Backtrace: command execution failed
Warning: targets not executed for mysql55: org.macports.install org.macports.build org.macports.destroot
Please see the log file for port mysql55 for details: