time_t is 64 bits on OpenBSD and NetBSD, so avoid truncation on those
platforms in a portable way.

Index: src/gmcerts.c
--- src/gmcerts.c.orig
+++ src/gmcerts.c
@@ -413,8 +413,8 @@ void deserializeTrusted_GmCerts(iGmCerts *d, iStream *
             const iRangecc key   = capturedRange_RegExpMatch(&m, 1);
             const iRangecc until = capturedRange_RegExpMatch(&m, 2);
             const iRangecc fp    = capturedRange_RegExpMatch(&m, 3);
-            time_t sec;
-            sscanf(until.start, "%ld", &sec);
+            long long sec;
+            sscanf(until.start, "%lld", &sec);
             iDate untilDate;
             initSinceEpoch_Date(&untilDate, sec);
             /* TODO: import method? */
