7.4: configure.ac: add build/ as macro-dir

[dilyanpalauzov]

Fixes https://bugs.php.net/bug.php?id=81637

Moved from #7666.

[nikic]

From the docs:

Starting from version 1.13, automake augments autoconf with a macro called AC_CONFIG_MACRO_DIRS, that provides a space-separated list of directories to use for looking up m4 files. The same macro will be available as part of autoconf 2.70.

So this requires autoconf 2.70, while our requirement is 2.68. We can't raise the requirement either, because this fails in CI, which has autoconf 2.69:

configure.ac:23: error: possibly undefined macro: AC_CONFIG_MACRO_DIRS

[dilyanpalauzov]

I use autoconf 2.69 and automake 1.16.5 . On my system, when AC_CONFIG_MACRO_DIRS is absent, libtoolize --force wants to put its files in ./m4, which does not exist. How about renaming the build directory to m4? This will have the same effect, as installing AC_CONFIG_MACRO_DIR.

Libtoolize uses AC_CONFIG_MACRO_DIR since https://git.savannah.gnu.org/cgit/libtool.git/commit/?id=4d644c39d835fe92878f1aace081ba46187fe4ca - for nine years now.

Moreover, the AC_CONFIG_MACRO_DIR is provided by … automake 1.13.2, released 2013, so it is a matter of installing on the servers newer automake.

[nikic]

PHP does not use automake.

[dilyanpalauzov]

What shall I run, after changing ext/openssl/config0.m4, and applying the patch for https://bugs.php.net/bug.php?id=75725 ?

I run autoreconf -visf, to consume the above change, and later on, make says that the used libtool version on the system is different from the libtool version bundled with PHP. To resolve this, I have to call libtoolize --force. Libtoolize does look for AC_CONFIG_MACRO_DIRS.

[nikic]

Normally you run ./buildconf after changes to m4 files.

To be clear, I'm okay with making changes to accommodate your non-standard workflow, but you need to introduce them in a way that does not break the build for everyone else.

[dilyanpalauzov]

Next time I upgrade, I will call ./buildconf and see what happens. For PHP 7.3 I deleted in addition aclocal.m4, but this file is gone in PHP 7.4.