Change the temporary directory search algorithm on Unix to allow directories
read and execute permission, but without read permission, to serve as temporary
directories. Apply this same standard to the "." fallback directory.
Changes backported into patch release 3.12.2 (2016-04-18):
Fix a backwards compatibility problem in version 3.12.0 and 3.12.1:
Columns declared as "INTEGER" PRIMARY KEY (with quotes around
the datatype keyword) where not being recognized as an
INTEGER PRIMARY KEY, which resulted in an incompatible database file.