According to Carsten Heinrici on 1/16/2010 5:45 AM: >> This scenario is described in the manual: >> http://www.gnu.org/software/autoconf/manual/autoconf.html#Expanded-Before-Required > > yes, I read this ... and tried to understand, but it is not too easy. > >> Without seeing your configure.ac, I can't tell you the exact fix, but it >> is likely to be a matter of using AC_REQUIRE in more places, or perhaps an >> AC_DEFUN_ONCE instead of AC_DEFUN of your macro that is wrapping the call >> to AC_PROG_CC. > > As far as I understood, it is caused by a direct expansion of > AC_PROG_CC within another macro FOO defined using AC_DEFUN, instead of > either > a) using AC_REQUIRE, or > b) m4_define(FOO). or > c) expanding AC_PROG_CC in the body of configure.ac > > The main problem is, that we want to support more compilers, named > differrently from the default list 'gcc cc' used by AC_PROG_CC. It's more than that - it is caused by direct expansion of AC_PROG_CC within another macro FOO, where FOO then calls macro BAR, and macro BAR uses AC_REQUIRE([AC_PROG_CC]). For discussion sake (since you haven't posted your original macros), I'm assuming you have: configure.ac: FOO foo.m4 AC_DEFUN([FOO], [ AC_PROG_CC([armcc tcc cl c51 and so on]) BAR ...]) bar.m4 AC_DEFUN([BAR], [AC_REQUIRE([AC_PROG_CC])]) > > Unfortunately, none of the options are satisfying: > a) does not support passing parameters to AC_PROG_CC AC_REQUIRE can pass arguments, it is just that the arguments are only honored by the first caller to AC_REQUIRE (and the documentation for calling AC_REQUIRE with arguments is sparse). That is, I think it can be as simple as patching foo.m4 as follows: AC_DEFUN([FOO], -AC_PROG_CC +AC_REQUIRE([AC_PROG_CC], [AC_PROG_CC([armcc tcc cl + c51 and so on])]) BAR ...]) > b) will not be supported by aclocal which requires AC_DEFUN and the > macro FOO is defined in another file Exactly, which is why I listed option C in the manual. > c) would require to change all configure.ac, and there are many of them No, that still only requires a change to foo.m4: AC_DEFUN([FOO], [ +AC_REQUIRE([FOO_BODY]) -AC_PROG_CC([armcc tcc cl c51 and so on]) BAR ...]) +AC_DEFUN([FOO_BODY], [ +AC_PROG_CC([armcc tcc cl c51 and so on]) +]) > The manual describes another solution, by changing the required macro, > but this would mean to change AC_PROG_CC. Correct - you can't change AC_PROG_CC (well, you can, by patching autoconf, but then everyone else running unpatched autoconf can't build your package; or you could redefine AC_PROG_CC, but that gets hairy to maintain). But you CAN change FOO, since it was FOO that had the problem in the first place. -- Don't work too hard, make some time for fun as well! Eric Blake ebb9@xxxxxxx
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