diff -ur xrootd-3.0.3.orig/configure.ac xrootd-3.0.3/configure.ac --- xrootd-3.0.3.orig/configure.ac 2011-04-11 13:24:37.000000000 +0200 +++ xrootd-3.0.3/configure.ac 2011-05-02 13:50:01.879165899 +0200 @@ -252,7 +252,7 @@ [AC_TRY_RUN([ int main() { - unsigned long val = 111, tmp, *mem = &val; + unsigned long long val = 111, tmp, *mem = &val; if (__sync_fetch_and_add(&val, 111) != 111 || val != 222) return 1; if (__sync_add_and_fetch(&val, 111) != 333) return 1;