fix --enable-laldetchar option help

laldetchar support is enabled by default, reflect this in the help
message for the option

(cherry picked from commit fc100e56bdd48b4a3e1eee6aa6ec50459a59ae43)
enable lalxml support by default

originally this was disabled by default as it linked against libxml2
which in turn was linked against the pthread library. as such this
caused problems as condor_compile could then not be used. however on the
current reference platorms libxml2 is not linked against pthreads.

(cherry picked from commit e4debc0c1dd5219c8b9e41e09cbd15fc826c92dc)