Locale.Charset: Fixed NULL-dereferencing in the decoder for EUC-CN and EUC-KR.

Thanks to 郭雪松 <zenothing@hotmail.com> for the bugreport.
Stdio.sendfile: Fixed handling of file length argument in nb_sendfile.

Fixes [bug 6118].
System.getgrent: The group member list can be NULL on MacOS X.

Potential fix for [bug 6187].
Fixed compat resolver fallback order.

The compat resolvers for old versions could sometimes skip
past the intermediate resolvers and go directly to the master.
Image.JPEG: Fix integer underflow. Fixes [bug 6413].
Release: bump version
Build: bump version
Runtime: Avoid use of negative array index in MAKE_{NAN,INF}

Apparently clang doesn't support indexing with a negative literal,
so switch the implementation to use unions instead, whenever possible.
(cherry picked from commit 6331fed0a6b5bab3b3ba7cae336b1b1b68096018)

Conflicts:

	src/port.h
Build: update copyright years
Build: update to newest export code, for git support.
First try at supporting MacOS X-style sendfile().

Rev: src/modules/files/sendfile.c:1.81
More fixes...

Rev: src/modules/files/sendfile.c:1.83
Fixed issue with sendfile() truncating files on MacOS X 10.5.x (current) and FreeBSD 4.x and earlier (old).

Rev: src/modules/files/acconfig.h:1.28
Rev: src/modules/files/configure.in:1.112
Rev: src/modules/files/sendfile.c:1.84
Build: Process.run doesn't exist in 7.6, so for now we'll include that function here.
Build: also, Process() doesn't exist, so we use Process.create_process().
Build: fix typo in export.pike that would trash version.h
release number bumped to 7.6.130 by export.pike
release number bumped to 7.6.131 by export.pike
CHANGELOG: update changes for new 7.6 release.
release number bumped to 7.6.132 by export.pike