"Empty body declaration" build failure(s) — clang 9.0.1

-Wempty-body warning is enabled by default which is not the case with gcc.
So, the following code will fail with clang but build with gcc:
int main() {
    if (1);
}
clang -Werror -c plop.c
gcc -Werror -c plop.c

No error detected for version 9.0.1