build-sys: check static linking of UBSAN

##########################################

# checks for sanitizers

write_c_skeleton

# we could use a simple skeleton for flags checks, but this also

# detect the static linking issue of ubsan, see also:

# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84285

cat > $TMPC << EOF

#include <stdint.h>

int main(void) {

  return INT32_MIN / -1;

}

EOF

have_asan=no

have_ubsan=no