Create and use struct_sysent and struct_ioctlent typedefs.

This is a preparatory mass replace patch with no code changes.

The future change will need to typedef sysent to sysent0,
which results in compile failures when "struct sysent" string
gets mangled into "struct sysent0".

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/strace.c b/strace.c
index 8d7ee74..900915e 100644
--- a/strace.c
+++ b/strace.c
@@ -2074,7 +2074,8 @@
 			if (pid == strace_child)
 				exit_code = 0x100 | WTERMSIG(status);
 			if (cflag != CFLAG_ONLY_STATS
-			    && (qual_flags[WTERMSIG(status)] & QUAL_SIGNAL)) {
+			 && (qual_flags[WTERMSIG(status)] & QUAL_SIGNAL)
+			) {
 				printleader(tcp);
 #ifdef WCOREDUMP
 				tprintf("+++ killed by %s %s+++\n",
@@ -2184,7 +2185,8 @@
  show_stopsig:
 #endif
 			if (cflag != CFLAG_ONLY_STATS
-			    && (qual_flags[sig] & QUAL_SIGNAL)) {
+			 && (qual_flags[sig] & QUAL_SIGNAL)
+			) {
 #if defined(PT_CR_IPSR) && defined(PT_CR_IIP)
 				long pc = 0;
 				long psr = 0;