LoadConfig() should be refactored to support both voice and language options set
in LoadVoice() and LoadLanguageOptions().

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

And make sure that the unfilled entries are NULL to catch any spurious
reference.

Also fix some missing phoneme table switch according to language
changes.

This works around issue 915

All sound file information goes to soundicon_tab. The contents of the files are not
loaded to memory before they are needed for synthesis.

This removes N_SOUNDICON_SLOTS that divided soundicon_tab into two
parts for unknown reasons.

TODO: LoadConfig() is currently undocumented. The logic should be
moved to LoadVoice() and documented.

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.

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

See commit 65847bd251. Bool recursing is not used for
anything anymore. Fixes a (compiler warning.

It is memset and set once, but never checked or used for anything.

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.

synthesize.h now contains the definitions STRESS_IS_... that should be used with code related to syllable stress.

Note that isBreak and other defines were renumbered so that stress definitions could have values 0-6.

Possible TODOs:
1. Unify with terms used with phonemes, i.e. keywords like isDiminished in compiledata.c and stress_type in phsource/phonemes
2. Add functionality and documentation about STRESS_IS_PRIORITY and STRESS_IS_EMPHASIZED

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.

This fixes the clang warning:

    comparison of unsigned expression < 0 is always false
    [-Wtautological-compare]

Reported by Reef Turner <[email protected]>

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