Boost 1.54: const class boost::filesystem::path' has no member named 'file_string'

... thus in trunk fails to compile plugin_libmysql_unix_socket_protocol_plugin

libtool: compile: g++-4.7 -DHAVE_CONFIG_H -I. -I. -I. -g -DPANDORA_MODULE_NAME=mysql_unix_socket_protocol -DPANDORA_MODULE_AUTHOR= -DPANDORA_MODULE_TITLE= -DPANDORA_MODULE_VERSION=2013.09.2642 -DPANDORA_MODULE_LICENSE=PLUGIN_LICENSE_GPL -DPANDORA_MODULE_DEPENDENCIES= -D_FORTIFY_SOURCE=2 -pthread -pipe -std=gnu++98 -O2 -pedantic -Wall -Wundef -Wshadow -fdiagnostics-show-option -fno-strict-aliasing -Wno-strict-aliasing -Wextra -Wformat -Wno-format-nonliteral -Wno-format-security -Woverloaded-virtual -Wnon-virtual-dtor -Wctor-dtor-privacy -Wno-long-long -Wmissing-declarations -Wframe-larger-than=32768 -Wredundant-decls -DBUILDING_DRIZZLED -pthread -g -O2 -fstack-protector --param=ssp-buffer-size=4 -Wformat -Werror=format-security -c plugin/mysql_unix_socket_protocol/protocol.cc -fPIC -DPIC -o plugin/mysql_unix_socket_protocol/.libs/plugin_libmysql_unix_socket_protocol_plugin_la-protocol.o
ln -s test-run.pl tests/test-run
ln -s kewpie.py tests/kewpie
plugin/mysql_unix_socket_protocol/protocol.cc: In member function 'virtual bool drizzle_plugin::mysql_unix_socket_protocol::Protocol::getFileDescriptors(std::vector<int>&)':
plugin/mysql_unix_socket_protocol/protocol.cc:170:27: error: 'const class boost::filesystem::path' has no member named 'file_string'
make[2]: *** [plugin/mysql_unix_socket_protocol/plugin_libmysql_unix_socket_protocol_plugin_la-protocol.lo] Fehler 1
make[2]: Leaving directory `/home/tobi/workspace/drizzle_build/gitorious/upstream/drizzle/trunk_nobzr'
make[1]: *** [all-recursive] Fehler 1
make[1]: Leaving directory `/home/tobi/workspace/drizzle_build/gitorious/upstream/drizzle/trunk_nobzr'
make: *** [all] Fehler 2