Squelch a few warnings on AIX. [skip appveyor]

See also tcpdump commit b7401ff.

* GCC 8.3.0 on AIX 7.1 and GCC 7.2.0 on AIX 7.2
./gencode.c: In function 'bpf_error':
./gencode.c:478:1: warning: 'noreturn' function does return

* GCC 8.3.0 on AIX 7.1
./optimize.c: In function 'opt_error':
./optimize.c:2424:1: warning: 'noreturn' function does return
./optimize.c: In function 'conv_error':
./optimize.c:2928:1: warning: 'noreturn' function does return

* XL C 12.1.0 on AIX 7.1 and XL C 13.1.3 on AIX 7.2:
"./nametoaddr.c", line 790.27: 1506-280 (W) Function argument assignment
between types "char*" and "const char*" is not allowed.

1 files changed, 6 insertions, 0 deletions

diff --git a/gencode.c b/gencode.c
index efdcb987..299d1c63 100644
--- a/gencode.c
+++ b/gencode.c
@@ -475,6 +475,12 @@ bpf_error(compiler_state_t *cstate, const char *fmt, ...)
 	va_end(ap);
 	longjmp(cstate->top_ctx, 1);
 	/*NOTREACHED*/
+#ifdef _AIX
+	/*
+	 * Same GCC workaround as in tcpdump.
+	 */
+	while (1);
+#endif /* _AIX */
 }
 
 static int init_linktype(compiler_state_t *, pcap_t *);