--- a/src/gctime.c
+++ b/src/gctime.c
@@ -1,14 +1,15 @@
+#include <string.h>
 typedef long f77_int;     /* Fortran integer type */
 typedef char * f77_char;    /* Fortran character argument */
 #define CH_F2C(X) ((char *) (X))  /* How to get char ptr from F77 argument */
-gctime (fstr, lstr) f77_char *fstr; int lstr; {
+int gctime (fstr, lstr) f77_char *fstr; int lstr; {
    long time(), t;
    char *ctime();
    t = time ( (long *) 0);
    strcpy(CH_F2C(fstr),ctime(&t));
    return (0);
    }
-gctime_(fstr, lstr) f77_char *fstr; int lstr; {
+int gctime_(fstr, lstr) f77_char *fstr; int lstr; {
    long time(), t;
    char *ctime();
    t = time ( (long *) 0);

--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.2)
+cmake_minimum_required(VERSION 3.5)