Fix a deadlock when GCing during a linda operation.

See issue #73.
Fix a compilation warning about an unused variable

Fix issue #74.
Get rid of uintptr_t to remove dependency on stdint.h

Fix issue #76.
Fix internal error at lane creation when the generator doesn't open any base library

Fix issue #77.
keeper.c: fix unsigned int cast of pointer

Signed-off-by: Steven Noonan <steven@uplinklabs.net>