small doc cleanups

[Ralf Wildenhues]

OK to apply these three patches affecting comments or documentation
only?

One reason I'm asking is that I tend to introduce errors when fixing
typos, and I'm unsure whether the Heirloom pointer is politically
correct.  standards.texi uses `@/' anyway now, so texinfo 4.6 is not
a new requirement (and anyway not needed for the default build).

Cheers,
Ralf

        * NEWS: Typo.
        * doc/autoconf.texi (Systemology): Mention the Heirloom Project.

        * doc/autoconf.texi (Introduction, Pointers): Use `@/' liberally
        in URLs to improve DVI formatted output (requires texinfo 4.6).
        (System Services, Systemology, Shellology): Likewise.
        (Limitations of Usual Tools): Rewrite Mac OS X example for nicer
        output.

        * doc/autoconf.texi (Fortran Compiler): Do not use address@hidden' in
        continuous text.
        (Runtime): Fix macro argument names to match description:
        `action-if-found' -> `action-if-true' and similarly.
        (Obsolete Macros): Likewise.
        * lib/autoconf/general.m4 (_AC_COMPILE_IFELSE): Likewise.
        (AC_COMPILE_IFELSE, AC_TRY_COMPILE, _AC_LINK_IFELSE)
        (AC_LINK_IFELSE, AC_TRY_LINK, AC_COMPILE_CHECK): Likewise.

doc-misc.diff
Description: Text document

doc-underfull.diff
Description: Text document

doc-variables.diff
Description: Text document