Add examples dir, built with BUILD_EXAMPLES=1 (Makefiles, no CMake equivalent yet).

Move tools/wpa to examples/wpa, and unbreak its build.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@88825 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/Makefile b/Makefile
index 22fe214..17ccc73 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,12 @@
 LEVEL = ../..
 DIRS := include lib tools docs
 
+PARALLEL_DIRS :=
+
+ifeq ($(BUILD_EXAMPLES),1)
+  PARALLEL_DIRS += examples
+endif
+
 include $(LEVEL)/Makefile.common
 
 ifneq ($(PROJ_SRC_ROOT),$(PROJ_OBJ_ROOT))