Add aligned_alloc to linker_memory.cpp

The new libc++_static.a platform prebuilt prefers to use this C11
function rather than the non-standard memalign.

Bug: http://b/175635923
Test: treehugger
Change-Id: I9c181568ba69c0508e400baac2cbb42b169c9768
diff --git a/linker/linker_memory.cpp b/linker/linker_memory.cpp
index 456d254..7ce53b8 100644
--- a/linker/linker_memory.cpp
+++ b/linker/linker_memory.cpp
@@ -76,6 +76,10 @@
   return get_allocator().memalign(alignment, byte_count);
 }
 
+void* aligned_alloc(size_t alignment, size_t byte_count) {
+  return get_allocator().memalign(alignment, byte_count);
+}
+
 void* calloc(size_t item_count, size_t item_size) {
   return get_allocator().alloc(item_count*item_size);
 }