Standard conforming boolean type

[Jiri Svoboda]

HelenOS uses, both in kernel and in userspace, a custom boolean type defined in bool.h, whose definition is similar to the ISO/IEC C99 standard boolean defined in stdbool.h.

Now that we expect to use a C99-conformant compiler, we can make the following change in both kernel and userspace:

• rename bool.h to stdbool.h
• bool shall be a macro that expands to the built-in type _Bool
• __bool_true_false_are_defined shall be a macro that expands to 1

this improves alignment with hosted implementation for userspace and freestanding implementation for kernel, as defined by the ISO/IEC C99 standard.

[Jiri Svoboda]

Fixed in mainline,1729. At the same time I removed posix/stdbool.h from libposix which did basically the same.