So valgrind can potentially catch e.g. missing \0.

So we know they are just tables, get protected from overflows, and get shared between processes

This works around issue 915

Soundicons are used for external audio with SSML <audio> tag and for
replacing punctuation names with sound files in LoadConfig().

Currently there's a bug wih soundicon slots: if both LoadConfig and
<audio> are used, the punctuation reserves all slots and no sound from
<audio> is played.

The SelectPhonemeTable(voice->phoneme_tab_ix) has no effect for tests.
Passing other values here breaks tests. That means that the relevant
calls SelectPhonemeTable() are already made in other functions.

voice->phoneme_tab_ix is set in LoadVoice().

wavefile_ix is always equal to fmt_params->wav_addr.

wavefile_amp is only used once  so it can be set right
before calling DoSample2().

this_ph_data, N_WAV_BUF, option.device, harm_sqrt_n,  max_hval, next_pause

Going through files in src/libespeak-ng/, include-what-you-use removed a
few unnecessary includes and included explanations on why a certain
header should be included. This makes tracking globals and dependencies easier.

Running the codebase through IWYU should be repeated after each major
code restIncludes to standard c library weren't checked to avoid
breaking builds with other platforms.

See https://github.com/include-what-you-use/include-what-you-use

There's two variables with the same name:
1) in struct PHONEME_DATA, used by *phdata, *phdata_next and *phdata_prev
2) an unnecessary one that's only being memset() twice but never used
   for anything

f_log is only used in compiledict.c.

It's only used in SpeakNextClause() and related to SelectPhonemeTable().

Another solution void be to keep SelectPhonemeTable() as a void function
and do a current_phoneme_table = voice->phoneme_tab_ix after the call to
SelectPhonemeTable().

This reverts commit d08b8e43ca.

This commit causes gcc-4.8 to output a different SHA1 hash on the
language-phonemes test for `af` (the first language tested). It
does not break on clang or on gcc-7 so may be a compiler bug,
however the Travis CI build server is using it on Ubuntu Trusty
(14.04 LTS) and so may other older OSes.

This makes the codebase more consistent. Including speech.h is not necessary anymore in some files. Includes have been removed.

See issue #8, https://github.com/espeak-ng/espeak-ng/issues/8

There might still be some ints that could be changed to boolean.

Possible regressions in fifo.c:
int fifo_is_busy() and int fifo_is_command_enabled() used to return an int. Now they return a boolean. This might cause problems on systems where stdbool true/false is something else than 1/0.

Moved include/espeak/speak_lib.h to include/espeak-ng/speak_lib.h and
created a symlink from the original location.

This function call does not affect the audio output in non-async
modes. Audio output in that case is handled within the SynthOnTimer
helper function.