Fix GH-1188: APCu Installation page is outdated

Author: cmb69

reference/apcu/book.xml

@@ -18,12 +18,7 @@
   </para>
   <para>
    The first APCu codebase was versioned 4.0.0, it was forked from the head of the APC master branch at the time.
-  </para>
-  <para>
-   PHP 7 support is available as of APCu 5.0.0.
-  </para>
-  <para>
-   APCu can provide a compatibility mode, such that it can provide a drop in replacement for the applicable parts of APC.
+   PHP 7 support is available as of APCu 5.0.0. PHP 8 support is available as of APCu 5.1.19.
   </para>
  </preface>
 

reference/apcu/setup.xml

@@ -15,24 +15,25 @@
    &pecl.info;
    <link xlink:href="&url.pecl.package;apcu">&url.pecl.package;apcu</link>.
   </para>
-  <para>
-   If backward compatibility with the applicable parts of APC is required,
-   APCu must be configured with the option --enable-apcu-bc.
-  </para>
+  <tip>
+   <simpara>
+    PHP 7 has a separate module (<link xlink:href="&url.apc.bc;">apcu-bc</link>) for backwards compatibility with APC.
+   </simpara>
+   <para>
+    In backward compatibility mode, APCu registers the applicable APC functions
+    with backward compatible prototypes.
+   </para>
+   <para>
+    Where an APC function accepted <parameter>cache_type</parameter>, it is simply
+    ignored by the backward compatible version, and omitted from the prototype for
+    the APCu version.
+   </para>
+  </tip>
   <warning>
    <simpara>
-    PHP 7 has a separate module (<link xlink:href="&url.apc.bc;">apc.so</link>) for backwards compatibility with APC.
+    As of PHP 8.0.0, apcu-bc is no longer supported.
    </simpara>
   </warning>
-  <para>
-   In backward compatibility mode, APCu registers the applicable APC functions
-   with backward compatible prototypes.
-  </para>
-  <para>
-   Where an APC function accepted <parameter>cache_type</parameter>, it is simply
-   ignored by the backward compatible version, and omitted from the prototype for
-   the APCu version.
-  </para>
   <note>
    <simpara>
     On Windows, APCu needs a temp path to exist, and be