decode() and transcode() now have an optional parameter length;
if length > 0, decode that many characters from the encoded string.

References #2421

This is mostly a mechanical patch.

For HEX and URL, there is now an ENUM case in {LOWER, UPPER} to
determine the case of hex digits produced for an encoding, default
LOWER.

Spotted by:	fgs

If the cli buffer is allocated on the stack, the mgt process will
crash hard for big values of this parameter. Instead we allocate on
the heap.

The new cli buffer an "auto" VSB. This means that the varnish
parameter cli_buffer is ignored from now on, and the manual marks it
as deprecated.

Closes: #2382

Don't attempt to free the static empty string that the VMOD assigns
for empty encodings.

blob objects.

Revealed by GCOV.

Works for all, check, install targets but not for individual targets,
see ref: https://www.gnu.org/software/automake/manual/html_node/Built-Sources-Example.html

Fixes #2423

The goal of `req.ttl` is to allow lower requirements for known
transactions (since this has to be done in VCL) but objects with
an age higher than `req.ttl` would always be considered expired
during lookup even if their actual TTL (obj.ttl) is still positive.

Ignoring `req.ttl` gives a better control over explicit refreshes
made to optimize latency and greatly reduces the risk of running
into #1799 (for a subset of use cases).

Closes #2422

$Event RST test again.

There are undoubtedly better ways, but I couldn't find them...

It's no longer used anyway, and was already called via the generic
VUT_Arg function.

We don't need an indirection in a separate C file per VUT.

- Revert to previous trusty image (ref. google/sanitizers/issues/837)
- Switch to xcode9 on osx
- Scaffolding to get the sanitizer job using clang 5.0
- ASAN: Disable stack protector
- ASAN: Ignore sigsegv and sigbus

Missed in 32877991.

This still needs more TLC! Please feel free to continue...

It got lost during the new world order megacommit
74328de8

varnishd writes its pids to vsm segments for vsm clients to
determine if varnishd processes are alive.

When running varnishd and vsm clients in different containers, the
pid information has no relevance and may even be ambiguous across
name spaces.

Setting the environment variable VSM_NOPID for vsm clients disables
use of pid information.

Patch by phk

indicated the process was present at one point.

Fixes #2420

Fixes #2419