Extending configure.ac

Greetings,

I was trying to add RapidJSON [1] to Octave. At first, I thought about
using AC_CHECK_LIB (after some reading in configure.ac, I noticed that
Octave uses the custom macro OCTAVE_CHECK_LIB which I think is the same
thing with some extra parameters.) But, since RapidJSON [1] is a
header-only library, I thought about using AC_CHECK_HEADER. Which option is
more preferable?

Also, should I stop the configure script (with AC_MSG_ERROR for example) If
the library is not found or should I disable the functions ? (I think the
latter is better. If it is, any source on how to do this will be helpful.)

Thanks in advance,
Abdallah

[1] https://rapidjson.org/