AC_REQUIRE fails to ensure ordering of macros

[Bruno Haible]

Hi,

Here I have a case where AC_REQUIRE([A]) at the beginning of macro B does
not guarantee that the textual expansion of A occurs before the textual
expansion of B.

Test case: http://www.haible.de/bruno/gnu/ac_require-bug.tar.gz
This tarball was generated with
  $ ./gnulib-tool --create-testdir --dir=... vasnprintf-posix

$ autoconf --version | head -1
autoconf (GNU Autoconf) 2.63

$ autoconf

The macro gl_MULTIARCH in glm4/multiarch.m4 contains only calls
to AC_COMPILE_IFELSE, AC_LANG_SOURCE, AC_DEFINE, AC_SUBST.

The macro gl_PRINTF_ENOMEM in glm4/printf.m4 starts with
  AC_REQUIRE([AC_PROG_CC])
  AC_REQUIRE([gl_MULTIARCH])

In the generated configure file you file the expansion of
  - gl_MULTIARCH at lines 11522..11592,
  - gl_PRINTF_ENOMEM at lines 9002..9201.

Same thing with autoconf 2.60..2.62. So if it's really an autoconf bug,
it must be a long-standing one.

Bruno