scan-build points out that bytes isn't read after it is assigned. While
this is not actually true (scan-build doesn't understand
__attribute__((__cleanup__)), which frees bytes), it's true that we
should ideally have an assertion here.

Signed-off-by: Simon McVittie <smcv@collabora.com>

scan-build complained that rest_argv_start could be used uninitialized,
because it can't see that rest_argc >= 2 implies that rest_argv_start
got initialized at the same time rest_argc was set. Make this easier
to understand.

Signed-off-by: Simon McVittie <smcv@collabora.com>

scan-build detected that ret was written but never read.

Signed-off-by: Simon McVittie <smcv@collabora.com>

scan-build detected that res was written but never read. Presumably
the use of ref here (carried over from the previous test) is a
copy/paste error.

Signed-off-by: Simon McVittie <smcv@collabora.com>

We always set match_len before using it, discarding the result of this
assignment. Detected by scan-build.

Signed-off-by: Simon McVittie <smcv@collabora.com>

This hasn't done anything useful since 0978826c: it just takes a
new ref to the installation, and then releases that ref without doing
anything with it. Detected by scan-build.

Signed-off-by: Simon McVittie <smcv@collabora.com>

scan-build has a lot of false positives for this codebase because it
doesn't understand __attribute__((__cleanup__)) or GLib's GError
convention, but it seems to have been right about these.

Signed-off-by: Simon McVittie <smcv@collabora.com>

Fixes #4234