The replacement tests for bs, hr, and sr are no longer marked as
broken as they work using the old code. The mk tests keep the
broken annotation, as they don't work in the old code either.

This reverts commit 801a8d197c.
This reverts commit 64d5701e5e.
This reverts commit 3b51ebf617.
This reverts commit 1fd235d2c0.
This reverts commit 9f0667de86.

PrepareLetters() function also could be used to set up letter groups A, B, C, etc. from string
and further could be loaded from configuration file

Fixes #511.

When .replace rule is used and -X switch is passed in runtime,
replaced characters should be shown in trace output.

as all other letters are already there from Cyrillic.

This reverts commit 6d751c93bf.

Fixes https://github.com/nvaccess/nvda/issues/8231.

When notably the audio card is busy, we should report the issue to the
application, but still permit the application to retry submitting text
to synth, and eventually succeed to open it.

This change simply fixes the update of the out_samplerate variable to track
whether audio is open, and if not when text is submitted by the application,
try again to open it.

Valgrind reports

==20307== Invalid write of size 1
==20307==    at 0x4E856FE: Wavegen.part.1 (wavegen.c:880)
==20307==    by 0x4E86682: Wavegen (wavegen.c:670)
==20307==    by 0x4E86682: Wavegen2 (wavegen.c:1235)
==20307==    by 0x4E86682: WavegenFill2 (wavegen.c:1317)
==20307==    by 0x4E86CA7: WavegenFill (wavegen.c:1398)
==20307==    by 0x4E7093F: Synthesize (speech.c:442)
==20307==    by 0x4E712E0: sync_espeak_Synth (speech.c:549)
==20307==    by 0x4E8A5C0: process_espeak_command (espeak_command.c:317)
==20307==    by 0x4E8B387: say_thread (fifo.c:333)
==20307==    by 0x50E85A9: start_thread (pthread_create.c:463)
==20307==    by 0x53F5CBE: clone (clone.S:95)
==20307==  Address 0xad5e1bd is 0 bytes after a block of size 2,205 alloc'd
==20307==    at 0x4C2CABF: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==20307==    by 0x4C2EE04: realloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==20307==    by 0x4E70CFC: espeak_ng_InitializeOutput (speech.c:286)
==20307==    by 0x4E6176E: espeak_Initialize (espeak_api.c:67)
==20307==    by 0x10A5D8: initialize_espeak (espeak.c:303)
==20307==    by 0x109D1D: main (espeakup.c:201)
==20307==

Indeed, the out_ptr >= out_end test is not enough: it only checks that
one byte can fit the buffer, while klatt and wavegen produce two bytes.

Prevents a segfault.