configure: Look for libcrypto even when configuring --without-krb4

Signed-off-by: Anders Kaseorg <andersk@mit.edu>
configure: Only use LIBCRYPTO_{CFLAGS,LIBS} on PKG_CHECK_MODULES success

Signed-off-by: Anders Kaseorg <andersk@mit.edu>
configure: Try openssl.pc after libcrypto.pc

OpenSSL < 0.9.8 didn’t ship libcrypto.pc.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>
Use CHECK_STR_AND_FREE more

We have this macro, why not use it?  (And it simplifies code a bit.)
WIP perlvariables
make gclosures work
WIP perlvariables
add cleanup function for perl variables
make new_variable_full take a get_default_fn parameter and lose the delete_fn parameter
expose owl_variable_make_closure (for use in new_variable_full) and rewrite owl_variable_get_default_tostring so that it actually works
rename variables in owl_variable_dict_add_from_list for clarity - 'cur' and 'var' aren't particularly helpful
style cleanup
fix memory leak
fix merge debris that broke build
fix memory corruption bug and what looks like the last memory leak
remove commented-out code
more fixes for string handling bugs
fix boolean variable default getter
add marshal typefile
properly initialize owl_variables created via the old perl api