How to extract defines from a header?

[stsp]

I tried a stackoverflow for that:
https://stackoverflow.com/questions/77558522/how-to-extract-defines-from-a-header
but seems no one knows an answer.

I'd like to get some defines from a
header and put them into a meson's
variables. I suppose the task can be
achieved by synthesizing run_command,
but I'd like meson to assist me with that,
so that I can run the pre-configured
preprocessor, use the pre-set include
paths, and so on.
In a Makefile I have to do:
VAR = $(shell echo MY_DEFINE | $(CPP) $(CPPFLAGS) -include my_hdr.h - | tail -n 1)
or something like this. Well, at least
I can use CPP and CPPFLAGS. But its
far from being ideal.
How can I do the same (or better) with meson?

[stsp]

Thanks @dcbaker !
I've got your suggestion to work
and posted an answer on stackoverflow.

incdir = include_directories('some_inc_dir')
cpp = meson.get_compiler('c')
VAR = cpp.get_define('MY_DEFINE',
  include_directories: incdir,
  prefix: '#include "my_hdr.h"')

[dcbaker]

I commented on stack overflow, but the prefix argument would save you the need for -include here.

[stsp]

Thanks, I edited replies to use prefix.