Prepare for a new netpgp-20091210 portable release.

Apart from infrastructure changes, there are the following functional ones:

+ Update to version 20091210

+ provide a new netpgp_match_list_keys(

Prepare for a new netpgp-20091210 portable release.

Apart from infrastructure changes, there are the following functional ones:

+ Update to version 20091210

+ provide a new netpgp_match_list_keys(3) function to perform a
regular-expression based search of all the keys in the keyring. If no
pattern is specified to match, then all keys are returned.

+ provide a new netpgp_set_homedir(3) function, and use it to set the
home directory from the library, rather than individually in all the
programs which use the library

+ provide a new netpgp_incvar(3) function which will add a constant
increment (which may be negative) to the value of an internal
variable. This is primarily used for the verbosity level within the
library, and is again a movement of the function into the library from
the individual programs which use the library

+ move to the specification of an ssh key file by internal variable,
rather than the directory holding an ssh key file

+ autoconf infrastructure changes

+ take a hammer to the _GNU_SOURCE definitions problems

+ don't rely on strnlen(3) being present everywhere

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Re-instate perl taint checking by re-defining the possible taint check in
swig. Fix a bug whereby the generated shlib_version file got appended to,
rather than rewritten.

Turns out that swig and tainted don't play well together - perl has no way
of knowing whether the memory will be modified. For now, the gross hack is
to switch off tainting

Add language bindings for tcl and perl