WebKit WPE assumes `libglesv2.so` is available on the host system
and uses `dlopen` to open it.
This patch starts using `ldconfig -p` to check if the library
exists on the system.
References #2745
The original plan was to rnu some checks against libc version the
binary is compiled with, but these turn out to be a little complicated:
parsing out libc version from both static binary and host system
requires text processing, and it's hard to make sure it works reliably
across distributions.
Instead, let's start with a very particular check against running
Firefox on Ubuntu 16.04.
References #2745
Missing dependencies is #1 problem with launching on Linux.
This patch starts validating browser dependencies before launching
browser on Linux. In case of a missing dependency, we will abandon
launching with an error that lists all missing libs.
References #2745
