Refactor linker allocator

Makes it reusable for different fixed sized and not very
big structures (<PAGE_SIZE).

Change-Id: Id5ec13fc6541b1935ef7fe3671c22b98685abbae
diff --git a/linker/Android.mk b/linker/Android.mk
index f0e6c13..d2bcfaf 100644
--- a/linker/Android.mk
+++ b/linker/Android.mk
@@ -6,6 +6,7 @@
     debugger.cpp \
     dlfcn.cpp \
     linker.cpp \
+    linker_allocator.cpp \
     linker_environ.cpp \
     linker_phdr.cpp \
     rt.cpp \
@@ -67,3 +68,5 @@
 LOCAL_INTERMEDIATE_TARGETS :=
 include $(LOCAL_PATH)/linker_executable.mk
 endif
+
+include $(call first-makefiles-under,$(LOCAL_PATH))