net/mpich: Unbreak on CURRENT with base clang 17

clang version 17.0.6 causes linker errors that break the build on
15.0-CURRENT.  Work around this by building with an older llvm from
ports. This patch is same as commit f25b169.

Thanks to thierry@ for the hint.

net/mpich/Makefile

@@ -78,6 +78,12 @@ CONFIGURE_ARGS=	--enable-fast=""	\
 
 .include <bsd.port.options.mk>
 
+.if ${OPSYS} == FreeBSD && ${OSVERSION} >= 1500005
+# linker error when compiling with llvm 17.0.6 on CURRENT
+USES+=			llvm:max=16
+CHOSEN_COMPILER_TYPE=	clang
+.endif
+
 .for pm in ${OPTIONS_GROUP_PM}
 . if ${PORT_OPTIONS:M${pm}}
 .  if empty(PMLIST)