devel/cmake: prefer python3 over versioned python3.x

Depending on which mechanism is used to find Python (Python3
in particular, since there's only one Python2 version left),
either python3 is found -- installed by the python3 metaport,
and presumed to be the "preferred / default Python3 version" --
of a versioned python3. Asking for, say, Python 3.6 will get
you whatever python3 points at -- assuming it is newer than 3.6 --
or, with the other mechanism, the newest python (e.g. highest
installed version). Those are not necessarily the same.

Switch the new mechanism to preferring python3; there's a
knob in CMake itself for that, we just need to set it in
the FreeBSD config-file.

PR:		252277

devel/cmake/Makefile

@@ -3,6 +3,7 @@
 PORTNAME=	cmake
 # Remember to update devel/cmake-doc and devel/cmake-gui as well.
 DISTVERSION=	3.22.2
+PORTREVISION=	1
 CATEGORIES=	devel
 MASTER_SITES=	https://github.com/Kitware/CMake/releases/download/v${DISTVERSION}/ \
 		https://www.cmake.org/files/v${PORTVERSION}/

devel/cmake/files/patch-Modules_Platform_FreeBSD.cmake

@@ -0,0 +1,12 @@
+--- Modules/Platform/FreeBSD.cmake.orig	2022-04-10 15:22:59 UTC
++++ Modules/Platform/FreeBSD.cmake
+@@ -26,4 +26,9 @@ foreach(type SHARED_LIBRARY SHARED_MODULE EXE)
+   set(CMAKE_${type}_LINK_DYNAMIC_C_FLAGS "-Wl,-Bdynamic")
+ endforeach()
+
++# Prefer python3 (installed by the python3 metaport) over the
++# highest-versioned Python3 interpreter, when asked for a non-exact
++# Python3 version.
++set(Python3_FIND_UNVERSIONED_NAMES FIRST)
++
+ include(Platform/UnixPaths)