Enable seamless compression for WIN32

In the archival code we pretend that WIN32 is a no-MMU platform and
use the new mingw_popen_fd routine to pipe data to/from commands
to compress/decompress.

The pretence is maintained by redefining MMU macros in bb_archive.h.
This is mostly used in the archival code but there are a handful
of places where it's used to access public interfaces.  The symbol
BB_ARCHIVE_PUBLIC is defined in these places.

With these changes:

   tar supports seamless compression/decompression
   rpm2cpio and dpkg-deb can be enabled

1 files changed, 4 insertions, 0 deletions

diff --git a/archival/cpio.c b/archival/cpio.c
index 454648d68..3cb7fdb35 100644
--- a/archival/cpio.c
+++ b/archival/cpio.c
@@ -374,6 +374,10 @@ int cpio_main(int argc UNUSED_PARAM, char **argv)
         argv += optind;
         if (opt & OPT_FILE) { /* -F */
                 xmove_fd(xopen(cpio_filename, O_RDONLY), STDIN_FILENO);
+#if ENABLE_PLATFORM_MINGW32
+                /* default is seek_by_read but seek_by_jump is OK for file */
+                archive_handle->seek = seek_by_jump;
+#endif
         }
 #else
         opt = getopt32(argv, OPTION_STR "oH:" IF_FEATURE_CPIO_P("p"), &cpio_filename, &cpio_fmt);