eloop: Default to using ppoll(2) again.

Even though we now have fully working kqueue(2) and epoll(7)
with our privsep code, ppoll(2) is faster and smaller for our
workload.

This time though, we will keep the code here as it's fully working
and while fixing kqueue we also fixed other bugs in dhcpcd as a result
so it's not time wasted at all.

1 files changed, 3 insertions, 55 deletions

diff --git a/configure b/configure
index 091815ab..07360a52 100755
--- a/configure
+++ b/configure
@@ -1221,61 +1221,9 @@ fi
 # Set this for eloop
 echo "#define	HAVE_REALLOCARRAY" >>$CONFIG_H
 
-if [ -z "$POLL" ]; then
-	printf "Testing for kqueue1 ... "
-	cat <<EOF >_kqueue1.c
-#include <sys/event.h>
-#include <sys/fcntl.h>
-#include <sys/time.h>
-int main(void) {
-	return kqueue1(O_CLOEXEC);
-}
-EOF
-	if $XCC _kqueue1.c -o _kqueue1 2>&3; then
-		POLL=kqueue1
-		echo "yes"
-	else
-		echo "no"
-	fi
-	rm -f _kqueue1.c _kqueue1
-fi
-
-if [ -z "$POLL" ]; then
-	printf "Testing for kqueue ... "
-	cat <<EOF >_kqueue.c
-#include <sys/types.h>
-#include <sys/event.h>
-#include <sys/time.h>
-int main(void) {
-	return kqueue();
-}
-EOF
-	if $XCC _kqueue.c -o _kqueue 2>&3; then
-		POLL=kqueue
-		echo "yes"
-	else
-		echo "no"
-	fi
-	rm -f _kqueue.c _kqueue
-fi
-
-if [ -z "$POLL" ]; then
-	printf "Testing for epoll ... "
-	cat <<EOF >_epoll.c
-#include <sys/epoll.h>
-int main(void) {
-	return epoll_create1(EPOLL_CLOEXEC);
-}
-EOF
-	if $XCC _epoll.c -o _epoll 2>&3; then
-		POLL=epoll
-		echo "yes"
-	else
-		echo "no"
-	fi
-	rm -f _epoll.c _epoll
-fi
-
+# Detect a polling mechanism.
+# See src/eloop.c as to why we only detect ppoll, pollts and pselect and
+# not others like epoll or kqueue.
 if [ -z "$POLL" ]; then
 	printf "Testing for ppoll ... "
 	cat <<EOF >_ppoll.c