Use explicit file protocol for AVIO

AVIO expects a `url` to locate a resource.

Use the file protocol to handle filenames containing colons.

Fixes #5487 <https://github.com/Genymobile/scrcpy/issues/5487>
PR #5499 <https://github.com/Genymobile/scrcpy/pull/5499>
Signed-off-by: Romain Vimont <rom@rom1v.com>

app/src/util/str.h

@@ -38,6 +38,15 @@ sc_str_join(char *dst, const char *const tokens[], char sep, size_t n);
 char *
 sc_str_quote(const char *src);
 
+/**
+ * Concat two strings
+ *
+ * Return a new allocated string, contanining the concatenation of the two
+ * input strings.
+ */
+char *
+sc_str_concat(const char *start, const char *end);
+
 /**
  * Parse `s` as an integer into `out`
  *