Headers including other headers?

[Jim Blandy <jimb@redhat.com>]

Suppose a header file in gdb/ contains code cannot be compiled without
definitions from other header files --- it uses typedefs, structures
in a way that requires their size, etc.  Is it more proper for the
header file to #include the other headers it requires itself, or
should it be the responsibility of the .c file #including it to also
bring in its prerequisites?

In hopes that this doesn't start a really long thread of unsatisfying
disagreements: I personally think that this is not a matter of huge
consequence either way, but it's nicer to have a consistent pattern,
so having someone simply establish any reasonable guideline is more
important than the actual details of that guideline.

I'm not volunteering to convert our existing headers; I just want to
know what style is recommended for new header files.