Add support for "platform" configurations, which define a suite of compiler-rt
libraries to generate.
 - Each library may be built with different flags and for different
   architectures, and there is support for building Darwin style fat archives.

 - Uses an ambituous amount of make programming, but should be hidden to
   users and developers.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@93720 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/make/lib_info.mk b/make/lib_info.mk
index 1c673f3..91ee23b 100644
--- a/make/lib_info.mk
+++ b/make/lib_info.mk
@@ -42,3 +42,8 @@
 $(foreach key,$(SubDirKeys),\
   $(foreach fn,$(basename $($(key).ObjNames)),\
     $(call Append,AvailableIn.$(fn),$(key))))
+
+# The names of all the available options.
+AvailableOptions := AR ARFLAGS \
+                    CC CFLAGS FUNCTIONS OPTIMIZED \
+                    RANLIB RANLIBFLAGS