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Re: 64-bit configure hell


Stan Shebs wrote:

The crux of the problem seems to be _AC_COMPILER_EXEEXT_WORKS in
autoconf's lang.m4, which looks like it fishes for a usable file
extension by trying to run programs with various names.

Isn't this what AC_NO_EXECUTABLES (also in lang.m4) is for?


from cvs autoconf's lang.m4:
# AC_NO_EXECUTABLES
# -----------------
# FIXME: The GCC team has specific needs which the current Autoconf
# framework cannot solve elegantly.  This macro implements a dirty
# hack until Autoconf is able to provide the services its users
# need.
#
# Several of the support libraries that are often built with GCC can't
# assume the tool-chain is already capable of linking a program: the
# compiler often expects to be able to link with some of such
# libraries.
#
# In several of these libraries, workarounds have been introduced to
# avoid the AC_PROG_CC_WORKS test, that would just abort their
# configuration.  The introduction of AC_EXEEXT, enabled either by
# libtool or by CVS autoconf, have just made matters worse.
#
# Unlike an earlier version of this macro, using AC_NO_EXECUTABLES does
# not disable link tests at autoconf time, but at configure time.
# This allows AC_NO_EXECUTABLES to be invoked conditionally.
AC_DEFUN_ONCE([AC_NO_EXECUTABLES],
[m4_divert_push([KILL])
m4_divert_text([DEFAULTS], [ac_no_link=no])

AC_BEFORE([$0], [_AC_COMPILER_EXEEXT])
AC_BEFORE([$0], [AC_LINK_IFELSE])

m4_define([_AC_COMPILER_EXEEXT],
[AC_LANG_CONFTEST([AC_LANG_PROGRAM()])
if AC_TRY_EVAL(ac_link); then
  ac_no_link=no
  ]m4_defn([_AC_COMPILER_EXEEXT])[
else
  ac_no_link=yes
  # Setting cross_compile will disable run tests; it will
  # also disable AC_CHECK_FILE but that's generally
  # correct if we can't link.
  cross_compiling=yes
  EXEEXT=
  _AC_COMPILER_EXEEXT_CROSS
fi
])

m4_define([AC_LINK_IFELSE],
[if test x$ac_no_link = xyes; then
  AC_MSG_ERROR([Link tests are not allowed after AC@&t@_NO_EXECUTABLES.])
fi
]m4_defn([AC_LINK_IFELSE]))

m4_divert_pop()dnl
])# AC_NO_EXECUTABLES

Peter
--
Peter O'Gorman - http://www.pogma.com


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