There were quite a few places were spaces were being used instead of
tabs. Try to catch them all. This should hopefully not break anything.
Except for `git blame`. Oh well.

1. The license header is technically not valid if it doesn't have a
copyright signature.

2. The COPYING file has been updated with the different licenses used in
the project.

3. The full GPLv2 header in each file annoys me.

Our good, lovely folks at Microsoft decided that there was no good
reason to make `vsnprintf` compilant with the C standard, so that
function in Windows returns -1 on overflow, instead of returning the
actual byte count needed to write the full string.

We now handle this situation more gracefully with the POSIX
compatibility layer, by returning the needed byte size using an
auxiliary method instead of blindly resizing the target buffer until it
fits.

This means we can now support `printf`s of any size by allocating a
temporary buffer. That's good.

The `stat` methods were having issues when called with a trailing slash
in Windows platforms.

We now use GetFileAttributes() where possible, which doesn't have this
restriction.

The old `git_fileops_prettify_path` has been replaced with
`git_path_prettify`. This is a much simpler method that uses the OS's
`realpath` call to obtain the full path for directories and resolve
symlinks.

The `realpath` syscall is the original POSIX call in Unix system and
an emulated version under Windows using the Windows API.

Cleaned up the structure of the whole OS-abstraction layer.

fileops.c now contains a set of utility methods for file management used
by the library. These are abstractions on top of the original POSIX
calls.

There's a new file called `posix.c` that contains
emulations/reimplementations of all the POSIX calls the library uses.
These are prefixed with `p_`. There's a specific posix file for each
platform (win32 and unix).

All the path-related methods have been moved from `utils.c` to `path.c`
and have their own prefix.

Win32 critical section objects (CRITICAL_SECTION) are not kernel objects.
Only kernel objects are destroyed by using CloseHandle.  Critical sections
are supposed to be deleted with the DeleteCriticalSection API
(http://msdn.microsoft.com/en-us/library/ms682552(VS.85).aspx).

We now depend on libpthread on all Unix platforms (should be installed
by default) and use a simple wrapper for Windows threads under Win32.

Signed-off-by: Vicent Marti <tanoku@gmail.com>

This will allow graceful migration to 64 bit file sizes and timestamps should
git's binary interface be extended to allow this.

This reduces the global namespace pollution and allows for
a win32 compiler (eg. Open Watcom) to provide these routines
in a header other than <dirent.h> (eg in <io.h>).

Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>

Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>

For information on FlushFileBuffers(), see the msdn document
at msdn.microsoft.com/en-us/library/aa364439(VS.85).aspx

Note that Windows 2000 is shown as the minimum windows version
to support FlushFileBuffers(), so if we wish to support Win9X
and NT4, we will need to add code to dynamically check if
kernel32.dll contains the function.

The only error return mentioned in the msdn document is
ERROR_INVALID_HANDLE, which is returned if the file/device
(eg console) is not buffered. The fsync(2) manpage says that
EINVAL is returned in errno, if "fd is bound to a special
file which does not support synchronization".

Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>

Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Signed-off-by: Andreas Ericsson <ae@op5.se>

Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Signed-off-by: Andreas Ericsson <ae@op5.se>

Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

In particular, the git__mmap() and git__munmap() routines provide
the interface to platform specific memory-mapped file facilities.
We provide implementations for unix and win32, which can be found
in their own sub-directories.

Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>