Align pool allocator with 8 byte in 64-bit environment.
To avoid warnings from undefined sanitizer.
( )
MODIFY
src/pool.c
src/pool.c
/* allocated memory address should be multiple of POOL_ALIGNMENT */
/* or undef it if alignment does not matter */
#ifndef POOL_ALIGNMENT
+#if INTPTR_MAX == INT64_MAX
+#define POOL_ALIGNMENT 8
+#else
#define POOL_ALIGNMENT 4
#endif
+#endif
/* page size of memory pool */
#ifndef POOL_PAGE_SIZE
#define POOL_PAGE_SIZE 16000

Align pool allocator with 8 byte in 64-bit environment.

To avoid warnings from undefined sanitizer.
( https://clang.llvm.org/docs/UndefinedBehaviorSanitizer.html )