This also avoids a warning with some compilers which do not understand
that the condition to initialize the variable is the same as the
condition to use it:
../app/src/scrcpy.c: In function ‘scrcpy’:
../app/src/scrcpy.c:750:13: warning: ‘src’ may be used uninitialized in this function [-Wmaybe-uninitialized]
750 | sc_frame_source_add_sink(src, &s->screen.frame_sink);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Refs 45fe6b602b4c050c5b1fba87cec7160093052af3
Refs <https://github.com/Genymobile/scrcpy/issues/5045#issuecomment-2201589757>
a4f8c02502