Revert "linker: get rid of the buddy allocator"

This reverts commit 7059b1f02ea9197728c851edd9ae0dd7688fa700.
Bug: 5036610
diff --git a/linker/Android.mk b/linker/Android.mk
index 60f291c..abe5995 100644
--- a/linker/Android.mk
+++ b/linker/Android.mk
@@ -8,7 +8,8 @@
 	linker_format.c \
 	rt.c \
 	dlfcn.c \
-	debugger.c
+	debugger.c \
+	ba.c
 
 ifeq ($(TARGET_ARCH),sh)
 # SH-4A series virtual address range from 0x00000000 to 0x7FFFFFFF.