The parser assumed that its input was a NUL-terminated string, but it
was not the case: it is just the raw output of "adb devices ip route".
In practice, it was harmless, since the output always ended with '\n'
(which was replaced by '\0' on truncation), but it was incorrect
nonetheless.
Always write a '\0' at the end of the buffer, and explicitly parse as a
NUL-terminated string. For that purpose, avoid the error-prone
sc_str_truncate() util function.
Now that providing a serial is mandatory for adb commands where it is
relevant, the whole argv array may be built statically, without
allocations at runtime.
If no serial is passed, then the command would work if there is exactly
one device connected, but will fail with multiple devices.
To avoid such cases, ensure that a serial is always provided.
On Windows, adb is provided in the release archive. Most missing adb
issues come from users setting the ADB environment variable to an
incorrect value (on all platforms).
Suggesting to install platform-tools to solve the problem will just make
things worse (there will be one more adb in yet another location).
