Support symlinks on Windows when core.symlinks=true
Enable `p_symlink` to actually create symbolic links, not just create a fake link (a text file containing the link target). This now means that `core.symlinks=true` works on Windows platforms where symbolic links are enabled (likely due to running in Developer Mode).
Now that we've updated to WIN32_WINNT version of Vista or better, we don't need to dynamically load GetFinalPathNameByHandle and can simply invoke it directly.
Update `git_win32_path_remove_namespace` to disambiguate the prefix being removed versus the prefix being added. Now we remove the "namespace", and (may) add a "prefix" in its place. Eg, we remove the `\\?\` namespace. We remove the `\\?\UNC\` namespace, and replace it with the `\\` prefix. This aids readability somewhat. Additionally, use pointer arithmetic instead of offsets, which seems to also help readability.
The internal API `git_win32__canonicalize_path` is far, far too easily confused with the internal API `git_win32_path_canonicalize`. The former removes the namespace prefix from a path (eg, given `\\?\C:\Temp\foo`, it returns `C:\Temp\foo`, and given `\\?\UNC\server\share`, it returns `\\server\share`). As such, rename it to `git_win32_path_remove_namespace`. `git_win32_path_canonicalize` remains unchanged.
C++ style comment ("//") are not specified by the ISO C90 standard and
thus do not conform to it. While libgit2 aims to conform to C90, we did
not enforce it until now, which is why quite a lot of these
non-conforming comments have snuck into our codebase. Do a tree-wide
conversion of all C++ style comments to the supported C style comments
to allow us enforcing strict C90 compliance in a later commit.
pack: rename `git_packfile_stream_free`
Currently, our memory allocators are being redirected to the correct implementation at compile time by simply using macros. In order to make them swappable at runtime, this commit reshuffles that by instead making use of a global "git_allocator" structure, whose pointers are set up to reference the allocator functions. Like this, it becomes easy to swap out allocators by simply setting these function pointers. In order to initialize a "git_allocator", our provided allocators "stdalloc" and "crtdbg" both provide an init function. This is being called to initialize a passed in allocator struct and set up its members correctly. No support is yet included to enable users of libgit2 to switch out the memory allocator at a global level.