move malloc implementation types and macros to an internal header

src/internal/malloc_impl.h

+#ifndef MALLOC_IMPL_H
+#define MALLOC_IMPL_H
+
+void *__mmap(void *, size_t, int, int, int, off_t);
+int __munmap(void *, size_t);
+void *__mremap(void *, size_t, size_t, int, ...);
+int __madvise(void *, size_t, int);
+
+struct chunk {
+	size_t psize, csize;
+	struct chunk *next, *prev;
+};
+
+struct bin {
+	volatile int lock[2];
+	struct chunk *head;
+	struct chunk *tail;
+};
+
+#define SIZE_ALIGN (4*sizeof(size_t))
+#define SIZE_MASK (-SIZE_ALIGN)
+#define OVERHEAD (2*sizeof(size_t))
+#define MMAP_THRESHOLD (0x1c00*SIZE_ALIGN)
+#define DONTCARE 16
+#define RECLAIM 163840
+
+#define CHUNK_SIZE(c) ((c)->csize & -2)
+#define CHUNK_PSIZE(c) ((c)->psize & -2)
+#define PREV_CHUNK(c) ((struct chunk *)((char *)(c) - CHUNK_PSIZE(c)))
+#define NEXT_CHUNK(c) ((struct chunk *)((char *)(c) + CHUNK_SIZE(c)))
+#define MEM_TO_CHUNK(p) (struct chunk *)((char *)(p) - OVERHEAD)
+#define CHUNK_TO_MEM(c) (void *)((char *)(c) + OVERHEAD)
+#define BIN_TO_CHUNK(i) (MEM_TO_CHUNK(&mal.bins[i].head))
+
+#define C_INUSE  ((size_t)1)
+
+#define IS_MMAPPED(c) !((c)->csize & (C_INUSE))
+
+#endif

src/malloc/malloc.c

@@ -8,54 +8,18 @@
 #include "libc.h"
 #include "atomic.h"
 #include "pthread_impl.h"
+#include "malloc_impl.h"
 
 #if defined(__GNUC__) && defined(__PIC__)
 #define inline inline __attribute__((always_inline))
 #endif
 
-void *__mmap(void *, size_t, int, int, int, off_t);
-int __munmap(void *, size_t);
-void *__mremap(void *, size_t, size_t, int, ...);
-int __madvise(void *, size_t, int);
-
-struct chunk {
-	size_t psize, csize;
-	struct chunk *next, *prev;
-};
-
-struct bin {
-	volatile int lock[2];
-	struct chunk *head;
-	struct chunk *tail;
-};
-
 static struct {
 	volatile uint64_t binmap;
 	struct bin bins[64];
 	volatile int free_lock[2];
 } mal;
 
-
-#define SIZE_ALIGN (4*sizeof(size_t))
-#define SIZE_MASK (-SIZE_ALIGN)
-#define OVERHEAD (2*sizeof(size_t))
-#define MMAP_THRESHOLD (0x1c00*SIZE_ALIGN)
-#define DONTCARE 16
-#define RECLAIM 163840
-
-#define CHUNK_SIZE(c) ((c)->csize & -2)
-#define CHUNK_PSIZE(c) ((c)->psize & -2)
-#define PREV_CHUNK(c) ((struct chunk *)((char *)(c) - CHUNK_PSIZE(c)))
-#define NEXT_CHUNK(c) ((struct chunk *)((char *)(c) + CHUNK_SIZE(c)))
-#define MEM_TO_CHUNK(p) (struct chunk *)((char *)(p) - OVERHEAD)
-#define CHUNK_TO_MEM(c) (void *)((char *)(c) + OVERHEAD)
-#define BIN_TO_CHUNK(i) (MEM_TO_CHUNK(&mal.bins[i].head))
-
-#define C_INUSE  ((size_t)1)
-
-#define IS_MMAPPED(c) !((c)->csize & (C_INUSE))
-
-
 /* Synchronization tools */
 
 static inline void lock(volatile int *lk)