diff --git a/newlib/libc/include/sys/signal.h b/newlib/libc/include/sys/signal.h
index 255782eb6..4bd841b80 100644
--- a/newlib/libc/include/sys/signal.h
+++ b/newlib/libc/include/sys/signal.h
@@ -244,7 +244,7 @@ int sigqueue (pid_t, int, const union sigval);
 
 /* POSIX Issue 8 adds sig2str() and str2sig() */
 
-#if __STDINT_EXP(INT_MAX) > 0x7fff
+#if __SIZEOF_INT__ >= 4
 #define SIG2STR_MAX (sizeof("RTMAX+") + sizeof("4294967295") - 1)
 #else
 #define SIG2STR_MAX (sizeof("RTMAX+") + sizeof("65535") - 1)