[Caml-list] [PATCH 0/2] use preprocessor to get infos about target arch

[Stefan Hellermann <stefan@the2masters.de>]

I'm trying to port OCaml to the openwrt router distribution [1]. Openwrt
makes heavy use of cross-compiling, and supports about 40 different
target archs.
When cross-compiling OCaml the configure script fails on 2 tests, it
cannot detect integer and pointer sizes and it cannot detect endianess.
I could now add rules and manually set the values for all 40 openwrt
targets into the configure script, but I think this doesn't scale well
and is only useful for openwrt.

So I sat down and wrote an alternative way to detect pointer sizes and
endianess by using the preprocessor and parsing it's output. This is
currently lightly tested on a few archs, so please comment and test.

There is also a test in configure script which checks if negative
division rounds to zero. This check currently fails in case of
cross-compile, but is only a warning. I see no way to do this check
in the preprocessor.
Is this test really needed? Which compiler do misbehave? Sind C99 round
to zero is mandated by the C Standard.

[1] https://openwrt.org/

Stefan Hellermann (2):
  configure: Check sizes of integers and pointers by using the
    preprocessor
  configure: Check endianess by using the preprocessor

 config/auto-aux/endian.c       | 60 ++++++++++++-----------------
 config/auto-aux/preprocesstest | 22 +++++++++++
 config/auto-aux/sizes.c        | 85 ++++++++++++++++++++++++++++++------------
 configure                      | 28 ++++++++------
 4 files changed, 123 insertions(+), 72 deletions(-)
 create mode 100755 config/auto-aux/preprocesstest

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2.1.4