Mingw port, status update

[Mike Hommey]

Hi,

Here's where I am standing with the mingw port: it passes the test
suite, and repeated running of test/thread_arena (which, until mutexes
were actually implemented, randomly failed :) )

The patches I'm currently using on top of current dev branch (5ff709c)
are:
- Replace %z in format strings with configure-time determined printf
  length modifier.
- Use a stub replacement and disable dss when sbrk is not supported.
- Call base_boot before chunk_boot0.

On top of these, I have a patch adding win32 support:
 configure.ac                                     |   25 ++++++-
 include/jemalloc/internal/jemalloc_internal.h.in |   11 ++-
 include/jemalloc/internal/mutex.h                |   16 +++-
 include/jemalloc/internal/tsd.h                  |   44 +++++++++++
 src/arena.c                                      |    2 +
 src/chunk_dss.c                                  |    5 +-
 src/chunk_mmap.c                                 |   87 +++++++++++++++++-----
 src/jemalloc.c                                   |   30 +++++++-
 src/mutex.c                                      |   10 ++-
 src/util.c                                       |    5 +-
 test/rallocm.c                                   |    9 +++
 11 files changed, 210 insertions(+), 34 deletions(-)

The remaining things to do:
- Build with the right extensions, the right flags, etc.
- Replace the madvise calls instead of removing them.
- Handle thread creation (equivalent to pthread_atfork)
- Call cleanup functions for tsd.

As mentioned in another message, the latter is tricky, as it basically
requires that all cleanup functions are called from a single point, so
we need to decide how to group them.

Equivalent to pthread_atfork is not a given, because while it is "easy"
to be notified of the creation of a thread through the dllmain entry
point (which means jemalloc needs to be a shared library, btw, because
executables don't have that), that only gives one half of the equation:
in the child, after thread creation. I haven't found a way to run
something in the parent before thread creation (at least yet).

For the madvise calls, I'm considering writing a "generic" function to
be used from both places madvise is called, I just need to know where to
put that (it would kind of make sense in chunk_mmap.h or chunk.h), and
what to name it.

This will only bring mingw support. MSVC will probably require more
tweaking, especially in the build system.

Cheers,

Mike