Merge #66: msvc: remove direct Bitcoin Core compat.h include

64f1758 msvc: remove Core compat.h include (fanquake)

Pull request description:

  My (untested) assumption is that this was only being used for a ssize_t
  definition. Remove the include, and define ssize_t to SSIZE_T.

  I'm planning on making a similar change in the Core codebase, and will pull a subtree update if this is merged.

  See:
  https://docs.microsoft.com/en-us/windows/win32/winprog/windows-data-types#ssize_t

ACKs for top commit:
  sipa:
    ACK 64f1758

Tree-SHA512: 02ff3284444a0f2ed4035b05ae9690c9dd8ae374a74d6567463bbbf58d1a3e7f6dfeda3f37b23e5275567d88cdb43daa2dde264a68dfb7d723832b37b51caf95

Author: sipa

include/minisketch.h

@@ -5,7 +5,8 @@
 #include <stdlib.h>
 
 #ifdef _MSC_VER
-#  include <compat.h>
+#  include <BaseTsd.h>
+   typedef SSIZE_T ssize_t;
 #else
 #  include <unistd.h>
 #endif