Make aligned_alloc() __wur too.

We made all the allocation functions in <malloc.h> __wur a while ago, but missed the one that's hidden in <stdlib.h> instead...

Change-Id: I53dd90fdac1a6f2da3d6f6edc1a3af1e23a4cdb9
diff --git a/libc/include/stdlib.h b/libc/include/stdlib.h
index 7c376d0..d2f3a65 100644
--- a/libc/include/stdlib.h
+++ b/libc/include/stdlib.h
@@ -75,7 +75,16 @@
 
 int posix_memalign(void* _Nullable * _Nullable __memptr, size_t __alignment, size_t __size);
 
-void* _Nullable aligned_alloc(size_t __alignment, size_t __size) __INTRODUCED_IN(28);
+/**
+ * [aligned_alloc(3)](https://man7.org/linux/man-pages/man3/aligned_alloc.3.html)
+ * allocates the given number of bytes with the given alignment.
+ *
+ * Returns a pointer to the allocated memory on success and returns a null
+ * pointer and sets `errno` on failure.
+ *
+ * Available since API level 28.
+ */
+__wur void* _Nullable aligned_alloc(size_t __alignment, size_t __size) __INTRODUCED_IN(28);
 
 double strtod(const char* _Nonnull __s, char* _Nullable * _Nullable __end_ptr);
 long double strtold(const char* _Nonnull __s, char* _Nullable * _Nullable __end_ptr);