--- a/configure.ac
+++ b/configure.ac
@@ -386,7 +386,7 @@ dnl  Digital Unix: stat
 time64_hack=no
 AH_TEMPLATE([TIME64_HACK], [time64 shuffle])
 AC_MSG_CHECKING([if we need to cope with time64])
-AC_EGREP_CPP([time64],[
+AC_EGREP_CPP([_*[a-z0-9]+_time64[^_]],[
 #include <bits/wordsize.h>
 #if __WORDSIZE == 32
 #define __USE_TIME_BITS64 1