we need the syscall6() version of mmap

ldso/include/dl-syscall.h

@@ -104,7 +104,7 @@ static inline _syscall0(gid_t, _dl_getpid);
 static inline _syscall3(int, _dl_readlink, const char *, path, char *, buf, size_t, bufsiz);
 
 #ifdef __NR_mmap
-#if defined(__powerpc__) || defined(__mips__) || defined(__sh__) || defined(__sparc__)
+#if defined(__powerpc__) || defined(__mips__) || defined(__sh__) || defined(__sparc__) || defined(__x86_64__)
 /* PowerPC, MIPS and SuperH have a different calling convention for mmap(). */
 #define __NR__dl_mmap __NR_mmap
 static inline _syscall6(void *, _dl_mmap, void *, start, size_t, length,