Add missing `git_reference_symbolic_create_with_log`.

It's exported in the headers, but the implementation was missing.
Allow the log message to be NULL.
Merge pull request #2023 from arthurschreiber/patch-1

Add missing `git_reference_symbolic_create_with_log`.
Add orig_commit.
Solaris does not have qsort_r
Merge pull request #2034 from jacquesg/solaris-qsort

Solaris doesn't have qsort_r either
Handle git_buf's from users more liberally
Merge pull request #2036 from ethomson/git_buf_sanitize

Handle git_buf's from users more liberally
Add orig & final commit test.
Merge pull request #2033 from xtao/blame_orig_commit

Add orig_commit.
branch: handle NULL pointers passed to git_branch_iterator_free()

Signed-off-by: Brodie Rao <brodie@sf.io>
config: handle NULL pointers passed to git_config_iterator_free()

Signed-off-by: Brodie Rao <brodie@sf.io>
odb: handle NULL pointers passed to git_odb_stream_free

Signed-off-by: Brodie Rao <brodie@sf.io>
oid: handle NULL pointers passed to git_oid_shorten_free()

Signed-off-by: Brodie Rao <brodie@sf.io>
refs: handle NULL pointers passed to git_reference_iterator_free()

Signed-off-by: Brodie Rao <brodie@sf.io>
util: handle NULL pointers passed to git_strarray_free()

Signed-off-by: Brodie Rao <brodie@sf.io>
Show informational messages during cmake run as informational
Merge pull request #2039 from brodie/brodie/handle-null-on-free

Fix places in public free() functions where NULL pointers aren't handled
Merge pull request #2040 from scunz/cmake_msgs

Show informational messages during cmake run as informational
Fix a memory leak in `git_pathspec__vinit`.