[PATCH 08/25] Use configure to detect HAVE_DECL_MMAP and use it for system doesn't provide sys/mman.h

[Mark Wielaard]

Hi,

On Sat, 2022-12-17 at 05:21 +0800, 罗勇刚(Yonggang Luo) wrote:
> On Fri, Oct 28, 2022 at 7:41 PM Mark Wielaard <mark@klomp.org> wrote:
> > On Fri, 2022-10-21 at 02:25 +0800, Yonggang Luo via Elfutils-devel
> > wrote:
> > > Signed-off-by: Yonggang Luo <luoyonggang@gmail.com>
> > > ---
> > >  configure.ac              | 1 +
> > >  lib/crc32_file.c          | 4 ++--
> > >  lib/system.h              | 2 ++
> > >  libelf/elf32_updatefile.c | 3 ++-
> > >  libelf/elf_begin.c        | 5 ++++-
> > >  libelf/elf_end.c          | 2 ++
> > >  libelf/elf_update.c       | 5 ++++-
> > 
> > Missing commit message and ChangeLog entries.
> > 
> > So this is for a system that doesn't have mmap?
> > How does the testsuite results look on such a system?
> > 
> > ELF_C_{READ,WRITE,RDWR}_MMAP[_PRIVATE] are elfutils extensions, but
> > they are used internally in other libraries.
> 
> I am trying getting elf support for windows/mingw/msvc, the  MMAP support
> is not needed yet
> for (QEMU/mesa)

I have to think what it means for a system that doesn't have mmap since
the mmap extensions are part of the public interface. And various parts
of the libraries depend on knowledge that they can read/write directly
from mmapped parts. Does it really make sense to try to support a
platform without mmap?

Cheers,

Mark