games/pysolfc: Fix runtime issues with Python 3.8+

* The deprecated function "time.clock()" has been removed in Python 3.8
  and "time.perf_counter()" should be used instead.

  Because updating to a newer version of PySolFC requires a bit more
  work, use a backport for now to remedy the runtime issues.

* Bump PORTREVISION due changed package contents.

PR:		256504
Reported by:	<sven.a.jonsson@bahnhof.se>
MFH:		2021Q2

(cherry picked from commit 91cf304355)

games/pysolfc/Makefile

@@ -1,7 +1,7 @@
 
 PORTNAME=	pysolfc
 DISTVERSION=	2.6.4
-PORTREVISION=	1
+PORTREVISION=	2
 CATEGORIES=	games python
 MASTER_SITES=	SF/${PORTNAME}/PySolFC/${PYSOLFCDIR} \
 		SF/${PORTNAME}/PySolFC-Cardsets/${CARDSETDIR}:cardsets

games/pysolfc/files/patch-pysollib_mfxutil.py

@@ -0,0 +1,21 @@
+Fix runtime errors with Python 3.8+ because the function time.clock() has been
+removed in Python 3.8, after having been deprecated since Python 3.3.
+
+Obtained from:
+https://github.com/shlomif/PySolFC/commit/0961401105850a18ff129e2c25cfffae45a81752
+
+--- pysollib/mfxutil.py.orig	2021-06-09 18:23:28 UTC
++++ pysollib/mfxutil.py
+@@ -143,7 +143,11 @@ def getprefdir(package):
+
+
+ # high resolution clock() and sleep()
+-uclock = time.clock
++try:
++    uclock = time.perf_counter
++except Exception:
++    uclock = time.clock
++
+ usleep = time.sleep
+ if os.name == "posix":
+     uclock = time.time