If parse_section_header{,_ext} return an error, current_section
doesn't get allocated. Set it to NULL after freeing so we don't try to
free it again.

This fixes part 2-2 of Issue #210.

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

Simplify cfg_readline and at the same time fix it so that it does
really ignore empty lines.

This fixes point 2-1 of Issue #210

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

On error, it would free the configuration object even though it didn't
own that memory, which would cause a double-free.

This fixes the first part of Issue #210

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

Fix compilation warnings in MSVC

This allows to successfully build libgit2 with waf on Windows.

When trying to inflate a buffer, a GIT_ERROR was returned when malloc()
failed.

Fix this to return GIT_ENOMEM.

git__delta_apply used to return with a generic GIT_ERROR when allocating
memory for the delta failed.

Fix this to return GIT_ENOMEM.