This avoids having to make LoadEnvelope2 pass &env_x[-1], which is very
strongly frowned upon by sanitizers such as usan.

https://github.com/espeak-ng/espeak-ng/issues/1072

Signed-off-by: Ulrich Müller <[email protected]>

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

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

Patch by Samuel Thibault.

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

This reverts commits 0cc0300328 to
38d15f8f90.

The 0cc03003 commit breaks MBROLA voice support. As such, there
may be other breakages in those commits.

This commit has been reported to cause distortions in phoneme
pitches and speeds.

Also use size_t instead of int in some places
where it make sense

This creates an fread compatible API on wxInputStream objects and
uses that API in LoadSpectSeq. This is to help the transition from
the wxWidgets wxInputStream API to the C FILE API.