A user noticed that gdb would crash when printing a packed array after
doing "set lang c". Packed arrays don't exist in C, but it's
occasionally useful to print things in C mode when working in a non-C
language -- this lets you see under the hood a little bit.
The bug here is that generic value printing does not handle packed
arrays at all. This patch fixes the bug by introducing a new function
to extract a value from a bit offset and width.
The new function includes a hack to avoid problems with some existing
test cases when using -fgnat-encodings=all. Cleaning up this code
looked difficult, and since "all" is effectively deprecated, I thought
it made sense to simply work around the problems.
e379f6521a