The local header file named as "signal.h" causes mysterious compile
error when built with an old glibc.
signal.h:27: error: conflicting types for 'sin_generator_init'
./signal.h:27: error: previous declaration of 'sin_generator_init' was here
signal.h:28: error: conflicting types for 'sin_generator_next_sample'
./signal.h:28: error: previous declaration of 'sin_generator_next_sample' was here
....
This turned out to be the conflict of signal.h; namely, pthread.h that
is included before our local signal.h also includes "pthread.h".
Since our local "signal.h" has a higher priority, it gets loaded
instead of the expected pthread's one. Then we load it again, and it
screws up.
Although it's basically a bug of pthread, it's anyway not good to have
a header file conflicting with the standard header file. So, let's
name it more explicitly as specific to BAT, bat-signal.h, for avoiding
such a conflict.
Signed-off-by: Takashi Iwai <tiwai@suse.de>