With gcc 7 we get warnings like the following:
fdasd.c: In function 'main':
fdasd.c:3055:4: warning: this statement may fall through
[-Wimplicit-fallthrough=]
fdasd_exit(&anchor, 0);
^~~~~~~~~~~~~~~~~~~~~~
fdasd.c:3056:3: note: here
default:
^~~~~~~
Fix this by marking functions with "__noreturn" to help gcc.
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>