Description:
------------
Hello,

package affected should be PECL Apcu which does not seem to exist in the Package affected list.

When calling ./configure --enable-apcu-mmap, the script decides to not use mmap, but when omitting that option it does use mmap.

./configure --help only documents disable-apcu-mmap, so either the documentation is wrong or the implementation because clearly "enable-apcu-mmap" is changing the behaviour in a neither expected nor documented way.

PHP Version: 7.1.2
APCU Version: 5.1.8

Reproduced on Gentoo and openSUSE Tumbleweed.

Greetings
Fabian

Test script:
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#!/bin/bash

wget "https://pecl.php.net/get/apcu-5.1.8.tgz"
tar xzf apcu-5.1.8.tgz
cd apcu-5.1.8/
phpize
./configure --enable-apcu-mmap | grep "checking if APCu will use mmap or shm"

Expected result:
----------------
checking if APCu will use mmap or shm... mmap

Actual result:
--------------
checking if APCu will use mmap or shm... shm