curses: ncurses may define curs_set outside of curses

This is a very poor design decision that sadly we need to work
around. There is no technical reason why all curses functions
are not defined in libcurses.

Thanks to Lars Wendler <polynomial-c@gentoo.org> for the initial patch.

Author: rsmarples

configure

@@ -462,11 +462,39 @@ int main(void) {
 EOF
 	if $XCC _curses.c -o _curses -lcurses 2>&3; then
 		LIB_CURSES=-lcurses
+		echo "$LIB_CURSES"
 	fi
 	rm -f _curses.c _curses
 fi
+
+# ncurses may have curs_set in libtinfo and not libcurses.
+# This is a very poor design as other curses implementations
+# do not have this limitation.
+if [ -n "$LIB_CURSES" ]; then
+	printf "Testing for curs_set in $LIB_CURSES ... "
+	cat <<EOF >_curses.c
+#include <curses.h>
+int main(void) {
+	curs_set(1);
+	return 0;
+}
+EOF
+	if $XCC _curses.c -o _curses $LIB_CURSES 2>&3; then
+		echo "yes"
+	else
+		if $XCC _curses.c -o _curses $LIB_CURSES -ltinfo 2>&3; then
+			echo "no (libtinfo)"
+			LIB_CURSES="$LIB_CURSES -ltinfo"
+		else
+			echo "no and not found"
+			[ "$WITH_CURSES" = yes ] && exit 1
+			LIB_CURSES=
+		fi
+	fi
+	rm -f _curses.c _curses
+fi
+
 if [ -n "$LIB_CURSES" ]; then
-	echo "$LIB_CURSES"
 	echo "LIB_CURSES=	$LIB_CURSES" >>$CONFIG_MK
 	UI="dhcpcd-curses${UI:+ }$UI"