Squashed 'deps/libgit2/' changes from d147900..4ceb388

4ceb388 Merge pull request #2784 from jacquesg/undef-stat
a1daec3 Undef stat first
ddf9532 Merge pull request #2783 from libgit2/cmn/treebuilder-new
61cf382 Merge pull request #2777 from sba1/amigaos-get-timer
7cf86f9 Added AmigaOS-specific implementation of git__timer().
208a2c8 treebuilder: rename _create() to _new()
aad27e6 Add a few missing CHANGELOG entries
5692dcf Merge pull request #2772 from ethomson/case_changing_rename
171c2ff Merge pull request #2778 from ethomson/whitespace_85
d6398d3 Merge pull request #2779 from ethomson/openssl_export
73f0278 global: include sys/openssl.h for GIT_EXPORT of fn
fe5f772 don't treat 0x85 as whitespace
40d7915 Always checkout with case sensitive iterator
61ee5b0 Introduce test for checkout case-changing rename
e8cd432 Merge pull request #2775 from ethomson/index_entrycounts
2fe8157 index: reuc and name entrycounts should be size_t
0bb237e Merge pull request #2773 from ethomson/findpkgconfig
6e1205e cmake: include FindPkgConfig for windows
62d66a4 Merge pull request #2745 from libgit2/cmn/pkg-config-ssh
4f91bfa Find libssh2 via pkg-config

git-subtree-dir: deps/libgit2
git-subtree-split: 4ceb388b13da61539f3b9df561c6050a0c5b6c31
Merge commit '337b0513ca932b4340d81f379bf8bf36aca457c0' into jacquesg/update-libgit2
Tree/Builder.xs: git_treebuilder_create() renamed to git_treebuilder_new()
Changes: update