foo.c: In function 'Concat':
foo.c:8:9: warning: unused variable 'len2' [-Wunused-variable]
    8 |     int len2 = strlen(s2);
      |         ^~~~
foo.c:9:5: warning: 'strncpy' specified bound depends on the length of the source argument [-Wstringop-truncation]
    9 |     strncpy(result, s1, len1 - 1);
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
foo.c:7:16: note: length computed here
    7 |     int len1 = strlen(s1);
      |                ^~~~~~~~~~

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