Replace obsolete AC_TRY_FOO with AC_FOO_IFELSE

[petk]

Hello,

Autoconf made several macros obsolete including the AC_TRY_COMPILE and AC_TRY_LINK in 2000 and since Autoconf 2.50: http://git.savannah.gnu.org/cgit/autoconf.git/tree/ChangeLog.2

These macros should be replaced with the current AC_FOO_IFELSE instead.

It is fairly safe to upgrade and take the recommendation advice of autoconf upgrade manual since the upgrade should be compatible at least with PHP versions 5.4 and up, on some systems even with PHP 5.3. PHP versions from 5.4 to 7.1 require Autoconf 2.59+ and PHP 7.2+ require Autoconf 2.64+.

This patch was created with the help of autoupdate script.

Reference docs:

• https://www.gnu.org/software/autoconf/manual/autoconf-2.69/html_node/Obsolete-Macros.html
• https://www.gnu.org/software/autoconf/manual/autoconf-2.59/autoconf.pdf

Thanks.

[sodabrew]

Hold up. This repo is based off the the upstream open source project php-memcached. I advise submitting the changes there.

[petk]

Of course, I've sent these to the php-memcached as well...

[petk]

Bump....