build: Add support for building dylibs.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@163412 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/make/lib_info.mk b/make/lib_info.mk
index 2e85f64..81f9695 100644
--- a/make/lib_info.mk
+++ b/make/lib_info.mk
@@ -53,8 +53,7 @@
 
 # The names of all the available options.
 AvailableOptions := AR ARFLAGS \
-                    CC CFLAGS FUNCTIONS OPTIMIZED \
+                    CC CFLAGS LDFLAGS FUNCTIONS OPTIMIZED \
                     RANLIB RANLIBFLAGS \
-                    VISIBILITY_HIDDEN \
-                    KERNEL_USE \
-                    STRIP LIPO
+                    VISIBILITY_HIDDEN KERNEL_USE \
+		    SHARED_LIBRARY STRIP LIPO