Added autodetection of available baud rates

Various platforms supports different baud rates.

To avoid adding platform specific handling generic baud rate detection
tests are introduced in the configure script. Successfully detected baud
rates are automatically enabled. This applies to both the C code and the
bash completion script.

Note:
Baud rates below 57600 are defined by POSIX-1 and supported by most
platforms so only baud rate 57600 and above are tested.

src/Makefile.am

@@ -14,6 +14,28 @@ tio_SOURCES = tty.c \
               include/tio/error.h
 
 if ENABLE_BASH_COMPLETION
+CLEANFILES = bash-completion/tio
+
+do_subst = sed -e 's/57600 /$(B57600) /g' \
+               -e 's/115200 /$(B115200) /g' \
+               -e 's/230400 /$(B230400) /g' \
+               -e 's/460800 /$(B460800) /g' \
+               -e 's/500000 /$(B500000) /g' \
+               -e 's/576000 /$(B576000) /g' \
+               -e 's/921600 /$(B921600) /g' \
+               -e 's/1000000 /$(B1000000) /g' \
+               -e 's/1152000 /$(B1152000) /g' \
+               -e 's/1500000 /$(B1500000) /g' \
+               -e 's/2000000 /$(B2000000) /g' \
+               -e 's/2500000 /$(B2500000) /g' \
+               -e 's/3000000 /$(B3000000) /g' \
+               -e 's/3500000 /$(B3500000) /g' \
+               -e 's/4000000/$(B4000000)/g'
+
+bash-completion/tio: bash-completion/tio.in
+	$(do_subst) < bash-completion/tio.in > bash-completion/tio
+
 bashcompletiondir=@BASH_COMPLETION_DIR@
 dist_bashcompletion_DATA=bash-completion/tio
+
 endif