Index: share/mk/src.opts.mk
===================================================================
--- share/mk/src.opts.mk
+++ share/mk/src.opts.mk
@@ -365,6 +365,14 @@
 __DEFAULT_NO_OPTIONS+=OPENMP
 .endif
 
+.if ${.MAKE.OS} != "FreeBSD"
+# Building the target compiler requires building tablegen on the host
+# which is (currently) not possible on non-FreeBSD
+BROKEN_OPTIONS+=CLANG LLD LLDB
+# The same also applies to the boostrap LLVM.
+BROKEN_OPTIONS+=CLANG_BOOTSTRAP LLD_BOOTSTRAP
+.endif
+
 .include <bsd.mkopt.mk>
 
 #