test-compress-benchmark: fix argument parsing on 32bit

The patch is not minimal, but a function to parse size_t is probably
going to come in handy in other places, so I think it's nicer to define
a proper parsing function than to open-code the cast.

src/basic/copy.c

@@ -71,7 +71,7 @@ static ssize_t try_copy_file_range(int fd_in, loff_t *off_in,
 int copy_bytes(int fdf, int fdt, uint64_t max_bytes, bool try_reflink) {
         bool try_cfr = true, try_sendfile = true, try_splice = true;
         int r;
-        size_t m = SSIZE_MAX; /* that the maximum that sendfile and c_f_r accept */
+        size_t m = SSIZE_MAX; /* that is the maximum that sendfile and c_f_r accept */
 
         assert(fdf >= 0);
         assert(fdt >= 0);

src/basic/parse-util.h

@@ -90,6 +90,18 @@ static inline int safe_atoli(const char *s, long int *ret_u) {
 }
 #endif
 
+#if SIZE_MAX == UINT_MAX
+static inline int safe_atozu(const char *s, size_t *ret_u) {
+        assert_cc(sizeof(size_t) == sizeof(unsigned));
+        return safe_atou(s, ret_u);
+}
+#else
+static inline int safe_atozu(const char *s, size_t *ret_u) {
+        assert_cc(sizeof(size_t) == sizeof(long unsigned));
+        return safe_atolu(s, ret_u);
+}
+#endif
+
 int safe_atod(const char *s, double *ret_d);
 
 int parse_fractional_part_u(const char **s, size_t digits, unsigned *res);

src/journal/test-compress-benchmark.c

@@ -164,7 +164,7 @@ int main(int argc, char *argv[]) {
                 arg_duration = x * USEC_PER_SEC;
         }
         if (argc == 3)
-                (void) safe_atolu(argv[2], &arg_start);
+                (void) safe_atozu(argv[2], &arg_start);
         else
                 arg_start = getpid();