i686-pc-linux-gnu bootstrap failure (Was: Re: building sh-elf / sh-linux)

[Joern Rennecke]

parse_in->opts.char_precision is overwritten because of a type layout
mismatch between parse_in->opts and cpp_opts.

In the stage1 cc1, I get:
(gdb) p sizeof cpp_opts->warn_invalid_pch
$12 = 4
(gdb) p sizeof parse_in->opts.warn_invalid_pch
$13 = 4

But in the stage1 cc1, I get:

(gdb) p sizeof cpp_opts->warn_invalid_pch
$46 = 1
(gdb) p sizeof parse_in->opts.warn_invalid_pch
$47 = 4

Something must have messed up the bool definition so that it is
inconsistent across modules.