Fix for wx-console build error

Fix for wx-console build error

For some reason, unknown to me, bacula build would fail if 'wx/config.h'
is included after 'bacula.h', with:

In file included from /usr/include/c++/4.7.2/i686-pld-linux/bits/gthr.h:150:0,
                 from /usr/include/c++/4.7.2/ext/atomicity.h:34,
                 from /usr/include/c++/4.7.2/bits/basic_string.h:41,
                 from /usr/include/c++/4.7.2/string:54,
                 from /usr/include/wx-2.8/wx/string.h:176,
                 from /usr/include/wx-2.8/wx/confbase.h:18,
                 from /usr/include/wx-2.8/wx/config.h:15,
                 from main.cpp:56:
/usr/include/c++/4.7.2/i686-pld-linux/bits/gthr-default.h:160:1: error: type of 'pthread_mutex_init' is unknown
/usr/include/c++/4.7.2/i686-pld-linux/bits/gthr-default.h:160:1: error: invalid type in declaration before ';' token
/usr/include/c++/4.7.2/i686-pld-linux/bits/gthr-default.h:161:1: error: type of 'pthread_mutex_destroy' is unknown
/usr/include/c++/4.7.2/i686-pld-linux/bits/gthr-default.h:161:1: error: invalid type in declaration before ';' token
/usr/include/c++/4.7.2/i686-pld-linux/bits/gthr-default.h: In function 'int __gthread_mutex_destroy(__gthread_mutex_t*)':
/usr/include/c++/4.7.2/i686-pld-linux/bits/gthr-default.h:760:52: error: '__gthrw_pthread_mutex_destroy' cannot be used as a function