[tz] [PROPOSED 4/5] Port TWOS_COMPLEMENT to signed-magnitude hosts

[Paul Eggert via tz]

* private.h (TWOS_COMPLEMENT): Port to signed-magnitude,
which is still used on Unisys Clearpath MCP (a C90 platform).
---
 private.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/private.h b/private.h
index 7e1e350a..42a1c892 100644
--- a/private.h
+++ b/private.h
@@ -943,7 +943,7 @@ ATTRIBUTE_PURE time_t time2posix_z(timezone_t, time_t);
 
 #define TYPE_BIT(type) (CHAR_BIT * (ptrdiff_t) sizeof(type))
 #define TYPE_SIGNED(type) (((type) -1) < 0)
-#define TWOS_COMPLEMENT(t) ((t) ~ (t) 0 < 0)
+#define TWOS_COMPLEMENT(type) (TYPE_SIGNED (type) && (! ~ (type) -1))
 
 /* Minimum and maximum of two values.  Use lower case to avoid
    naming clashes with standard include files.  */
-- 
2.51.0