devel/llvm12: mark incompatible with python 3.10

This limitation is inherited from py-sphinx and should be recondidered when it's updated

Approved by:	portmgr blanket

devel/llvm12/Makefile

@@ -31,7 +31,7 @@ DATADIR=	${PREFIX}/share/${PORTNAME}${LLVM_SUFFIX}
 
 USES=		cmake compiler:c++11-lib perl5 tar:xz \
 		shebangfix
-_USES_PYTHON?=	python:3.6+,build
+_USES_PYTHON?=	python:3.6-3.9,build
 USES+=		${_USES_PYTHON}
 USE_LDCONFIG=	${LLVM_PREFIX}/lib
 SHEBANG_FILES=	llvm/utils/lit/lit.py llvm/utils/llvm-lit/llvm-lit.in \
@@ -140,7 +140,7 @@ GOLD_DESC=		Build the LLVM Gold plugin for LTO
 GOLD_CMAKE_ON=		-DLLVM_BINUTILS_INCDIR=${LOCALBASE}/include
 GOLD_BUILD_DEPENDS=	${LOCALBASE}/bin/ld.gold:devel/binutils
 LIT_DESC=		Install lit and FileCheck test tools
-LIT_VARS=		_USES_PYTHON=python:3.6+
+LIT_VARS=		_USES_PYTHON=python:3.6-3.9
 LLD_DESC=		Install lld, the LLVM linker
 LLDB_BUILD_DEPENDS=	swig:devel/swig
 LLDB_CMAKE_ON=		-DLUA_INCLUDE_DIR=${LOCALBASE}/include/lua${LUA_VER_STR} \
@@ -153,12 +153,12 @@ LLDB_CMAKE_ON=		-DLUA_INCLUDE_DIR=${LOCALBASE}/include/lua${LUA_VER_STR} \
 LLDB_DESC=		Install lldb, the LLVM debugger
 LLDB_IMPLIES=		CLANG
 LLDB_USES=		lua:53 libedit
-LLDB_VARS=		_USES_PYTHON=python:3.6+
+LLDB_VARS=		_USES_PYTHON=python:3.6-3.9
 OPENMP_DESC=		Install libomp, the LLVM OpenMP runtime library
 OPENMP_PORTDOCS=	openmp
 PYCLANG_DESC=	Install python bindings to libclang
 PYCLANG_IMPLIES=	CLANG
-PYCLANG_VARS=	_USES_PYTHON=python:3.6+
+PYCLANG_VARS=	_USES_PYTHON=python:3.6-3.9
 PYCLANG_CMAKE_ON= -DCLANG_PYTHON_BINDINGS_VERSIONS=${PYTHON_VER}
 
 .if defined(WITH_DEBUG)