The code to handle in-memory db exceptions is hideous and unreliable,
given the fact that SQLite does not expose much in terms of getting the
current value and the methods to check the compile time options can
themselves be disabled by a compile=time option in SQLite.
There really isn't much use for in-memory databases and if someone
really needs it, they can always choose to run in normal mode, so just
remove the extra code.
* Remove some of the obsolete macros.
* Use AC_CONFIG_MACRO_DIR to allow compatibility with older versions of
autoconf.
* Remove AU_ALIAS from curses macro.
On some systems, sqlite3 requires pthread libraries to be linked in. Add
the flag so that autoconf can successfully compile and look for
'sqlite3_open'.
The current macro does not seem to honor the CFLAGS and LDFLAGS
variables if '--with-sqlite3=yes' is used. Fix this and some of
the other cruft in the macro.
