Replace uses of obsolete autoconf macros in Jim's modules.
The Autoconf macros AC_TRY_CPP, AC_TRY_COMPILE, AC_TRY_LINK and
AC_TRY_RUN have been obsolete since Autoconf 2.55, and each use
can evoke a warning from autoconf when run with -Wobsolete
enabled. They were declared obsolete for good reasons (see
the `AC_FOO_IFELSE vs AC_TRY_FOO' node in the Autoconf manual,
recently renamed to `AC_ACT_IFELSE vs AC_TRY_ACT'), and we
should not continue using the deprecated macros.