update syscalls with off_t arguments to handle argument alignment, if needed

the arm syscall abi requires 64-bit arguments to be aligned on an even
register boundary. these new macros facilitate meeting the abi
requirement without imposing significant ugliness on the code.
diff --git a/src/fcntl/posix_fadvise.c b/src/fcntl/posix_fadvise.c
index 75edafa..2170209 100644
--- a/src/fcntl/posix_fadvise.c
+++ b/src/fcntl/posix_fadvise.c
@@ -3,6 +3,6 @@
 
 int posix_fadvise(int fd, off_t base, off_t len, int advice)
 {
-	return -__syscall(SYS_fadvise, fd, __SYSCALL_LL(base),
-		__SYSCALL_LL(len), advice);
+	return -(__syscall)(SYS_fadvise, fd, __SYSCALL_LL_O(base),
+		__SYSCALL_LL_E(len), advice);
 }