AC_C_INLINE on recent HP C

[Kevin Ryde]

A recent version of HP C (B.11.11.04) doesn't seem to like "inline"
functions returning typedefs, only builtin types.  I'd like to propose
including a typedef in the AC_C_INLINE test program to avoid inline on
that compiler.

Perhaps some programs will only need plain types as return values, but
since this is almost certainly a compiler bug it doesn't seem worth
worrying about that distinction.

        * lib/autoconf/c.m4 (AC_C_INLINE): Test with a typedef return value,
        to avoid versions of HP C which don't allow that.

c.m4.hpinline.diff
Description: Source code patch