PHP5 packages can be installed on one 16.04 system but not on another

[Chris Green]

On Wed, May 18, 2016 at 11:16:04AM +0100, Chris Green wrote:
> I have two xubuntu 16.04 systems both with LAMP server software on
> them.  On one I can see and successfully install a number of PHP5
> packages, in particular php5-sqlite, on the other it can't see this
> package at all using apt-search or synaptic.
> 
> I have checked through all the repsitories in /etc/apt and, as far as
> I can see, they're identical.
> 
> What is wrong?  I need php5-sqlite on both systems.
> 
I have diff'ed /etc/apt/sources.list between the two systems, it's
identical.

Here's the result of 'apt-cache search php5' on the system which can't
get php5-sqlite:-

    chris$ apt-cache search php5
    php-auth - Creating an authentication system
    php-doc - Documentation for PHP5
    php-letodms-lucene - Document management system - Fulltext search
    php-memcache - memcache extension module for PHP5
    php-memcached - memcached extension module for PHP5, uses libmemcached
    phpunit - Unit testing suite for PHP5
    bluefish - advanced Gtk+ text editor for web and software development
    phing - PHP5 project build system based on Apache Ant
    php-http-request2 - Provides an easy way to perform HTTP requests
    php-net-dns2 - PHP5 Resolver library used to communicate with a DNS server


... and here's the output on the good system:-

    chris at t430$ apt-cache search php5
    php-auth - Creating an authentication system
    php-doc - Documentation for PHP5
    php-letodms-lucene - Document management system - Fulltext search
    php-memcache - memcache extension module for PHP5
    php-memcached - memcached extension module for PHP5, uses libmemcached
    phpunit - Unit testing suite for PHP5
    bluefish - advanced Gtk+ text editor for web and software development
    phing - PHP5 project build system based on Apache Ant
    php-http-request2 - Provides an easy way to perform HTTP requests
    php-net-dns2 - PHP5 Resolver library used to communicate with a DNS server
    libapache2-mod-php5 - server-side, HTML-embedded scripting language (Apache 2 module)
    php5-json - JSON module for php5
    php5-readline - Readline module for php5
    php5-cli - command-line interpreter for the php5 scripting language
    php5-common - Common files for packages built from the php5 source
    php5-sqlite - SQLite module for php5

What on earth is going on?

-- 
Chris Green