Adds recent Windows 10 support to the drstrace and drltrace tools.
Includes miscellaneous bug fixes.

Includes preliminary 64-bit support on Mac OSX 10.15 Catalina.
Fixes DynamoRIO/dynamorio#4081, a Mach-O indirect symbol lookup bug causing crashes.
This Mac support is in the alpha stage.
It is only expected to work with small single-threaded Mac applications.
It is for experimental evaluation purposes.

See also the changelist at
https://github.com/DynamoRIO/drmemory/blob/release_2.3.0/drmemory/docs/release.dox#L63.