nginx: improved image_filter check as it also relies in libjpeg and libpng

network/nginx/nginx.conf

@@ -40,7 +40,7 @@ var_append confopt ' ' "--http-log-path=$logdir/access.log"
 var_append confopt ' ' "--error-log-path=$logdir/error.log"
 
 # --with- with dependency
-for x in openssl:ssl libgd:image_filter zlib:gzip_static; do
+for x in openssl:ssl zlib:gzip_static; do
 	if pkginstalled "${x%:*}"; then
 		var_append confopt ' ' "--with-http_${x#*:}_module"
 	fi
@@ -58,6 +58,19 @@ for x in stub_status flv realip; do
 	var_append confopt ' ' "--with-http_${x}_module"
 done
 
+# image_filter
+has_all=yes
+for x in libgd libjpeg libpng; do
+	if ! pkginstalled "$x"; then
+		has_all=no
+		break
+	fi
+done
+if [ "$has_all" = "yes" ]; then
+	var_append confopt ' ' "--with-http_image_filter_module"
+fi
+unset has_all
+
 if atstage cross; then
 	var_append configprefix ' ' 'cross_compiling=yes'