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.

Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>

This will make libgit2 more suitable for embedding.

The visibility attribute is a headache on many platforms like Solaris,
and not even supported on Windows.

The assertion in line 360 was there to check that only loose refs were
being written as loose, but there are times when we need to re-write a
packed reference as loose.

filebuf: fix endless loop on writing buf > WRITE_BUFFER_SIZE

GIT_EXTERN'd  head_detached() and head_orphan()

Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>

Hide ".git" directory on Windows upon creation of a non bare repository

Directory which name starts with a dot are hidden on Linux platforms. This patch makes libgit2 behaves similarly on Windows.

`git_reference_rename` now takes a `force` flag

Signed-off-by: Carlos Martín Nieto <carlos@cmartin.tk>

Core Git doesn't care when people use spaces in the email address, even
though this kind of foolery receives the capital punishment in several
states of the USA.

We must obey.

Add detached and orphan convenience functions

Fix warning: signed and unsigned type in cond expr

A bunch of redundant methods have been removed from the external API.

- All the reference/tag creation methods with `_f` are gone. The force
flag is now passed as an argument to the normal create methods.

- All the different commit creation methods are gone; commit creation
now always requires a `git_commit` pointer for parents and a `git_tree`
pointer for tree, to ensure that corrupted commits cannot be generated.

- All the different tag creation methods are gone; tag creation now
always requires a `git_object` pointer to ensure that tags are not
created to inexisting objects.

Signed-off-by: Carlos Martín Nieto <cmn@elego.de>

Signed-off-by: Carlos Martín Nieto <cmn@elego.de>

Remove call of gitfo_size, since we call gitfo_lstat anyway; remove some
old workaround code for gitfo_read, which is obsolete now.

Signed-off-by: schu <schu-github@schulog.org>

Bring back GCC flags

Signed-off-by: Carlos Martín Nieto <carlos@cmartin.tk>

added defines for Haiku in types.h

gitfo_read: fix read-loop

Two memory access fixes