Clean mixed declarations and code

No functional changes, but will allow to remove -std=gnu99 from
the CFLAGS.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
add evemu-test-runner into .gitignore

The file is generated during make, so not need to track it.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
remove -D_GNU_SOURCE=1 from CFLAGS

The macro _GNU_SOURCE is only required in evemu-event. So remove
it from the global CFLAGS and add it directly in the required
source file.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
disable -Werror in CFLAGS

If someone really wants -Werror, they can set it in $CFLAGS.

Furthermore, Mattsch wrote (lp #1095836):

It's best practice to not enable -Werror:

https://blog.flameeyes.eu/2009/02/future-proof-your-code-dont-use-werror
https://bugs.gentoo.org/show_bug.cgi?id=Werror
http://devmanual.gentoo.org/ebuild-writing/common-mistakes/index.html

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
evemu-recorder: do not give up after 10 s if no events are available

There is no point in waiting only for 10 seconds.
10 seconds is not enough sometimes.
Just wait for an infinite time.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>