I think Apple does very similarly, but probably with a stack size of 16.
We do it with a stack size that is currently set to 64.

Fixes https://github.com/harfbuzz/harfbuzz/issues/1531

Before we used to give up.  Now, just ignore error and continue processing.

Fixes https://github.com/harfbuzz/harfbuzz/issues/1531

Fixes https://bugs.chromium.org/p/chromium/issues/detail?id=924848

Fixes https://github.com/harfbuzz/harfbuzz/issues/1556

Adjust tests.

Fixes https://github.com/harfbuzz/harfbuzz/issues/1532

Fixes MORX-31

Clang and gcc know not to warn in these cases, but not nonmainstream compilers

If compiler doesn't inline StructAtOffset, this was an error since we
only disable cast-align at call-site.  So, move the cast out.

../src/hb-machinery.hh: In instantiation of 'const Type& StructAtOffset(const void*, unsigned int) [with Type = unsigned int]':
../src/hb-font.cc:146:85:   required from here
../src/hb-machinery.hh:63:12: error: cast from 'const char*' to 'const unsigned int*' increases required alignment of target type [-Werror=cast-align]
 { return * reinterpret_cast<const Type*> ((const char *) P + offset); }
            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../src/hb-machinery.hh: In instantiation of 'Type& StructAtOffset(void*, unsigned int) [with Type = unsigned int]':
../src/hb-font.cc:147:79:   required from here
../src/hb-machinery.hh:66:12: error: cast from 'char*' to 'unsigned int*' increases required alignment of target type [-Werror=cast-align]
 { return * reinterpret_cast<Type*> ((char *) P + offset); }
            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We don't support that version anymore.

Fixes https://github.com/harfbuzz/harfbuzz/issues/1553

Part of https://github.com/harfbuzz/harfbuzz/issues/1553

Part of https://github.com/harfbuzz/harfbuzz/issues/1553

Part of https://github.com/harfbuzz/harfbuzz/issues/1553