microsoft/spirv_to_dxil: Use non-zero exit code on failed compilations

Reviewed-by: Jesse Natalie <jenatali@microsoft.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/10064>

src/microsoft/spirv_to_dxil/spirv2dxil.c

@@ -140,6 +140,7 @@ main(int argc, char **argv)
       spirv_to_dxil_free(data);
    } else {
       fprintf(stderr, "Compilation failed\n");
+      return 1;
    }
 
    free(file_contents);