Support for experimental targets

Added LLVM_EXPERIMENTAL_TARGETS_TO_BUILD in CMake and --enable-experimental-targets in configure.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161561 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/autoconf/configure.ac b/autoconf/configure.ac
index 4d3a14e..4dde3a6 100644
--- a/autoconf/configure.ac
+++ b/autoconf/configure.ac
@@ -717,6 +717,17 @@
   done
   ;;
 esac
+
+AC_ARG_ENABLE([experimental-targets],AS_HELP_STRING([--enable-experimental-targets],
+    [Build experimental host targets: disable or target1,target2,...
+     (default=disable)]),,
+    enableval=disable)
+
+if test ${enableval} != "disable"
+then
+  TARGETS_TO_BUILD="$enableval $TARGETS_TO_BUILD"
+fi
+
 AC_SUBST(TARGETS_TO_BUILD,$TARGETS_TO_BUILD)
 
 dnl Determine whether we are building LLVM support for the native architecture.