core: Apply default options to all new contexts

The default options configured with libusb_set_option(NULL, ...)
were only applied when the default context was created, and were
ignored when calling libusb_init() with a non-null context pointer.

Make sure the default options will be applied to all new contexts. This
is important when using LIBUSB_OPTION_NO_DEVICE_DISCOVERY which must
be respected during the context initialization in order to work.

Closes #942

[Tormod: amend comments]
Signed-off-by: Tormod Volden <debian.tormod@gmail.com>
diff --git a/libusb/core.c b/libusb/core.c
index 3d2f2b4..e6dca8b 100644
--- a/libusb/core.c
+++ b/libusb/core.c
@@ -2316,12 +2316,8 @@
 	list_init(&_ctx->usb_devs);
 	list_init(&_ctx->open_devs);
 
-	/* default context should be initialized before calling usbi_dbg */
-	if (!ctx) {
-		usbi_default_context = _ctx;
-		default_context_refcnt = 1;
-		usbi_dbg(usbi_default_context, "created default context");
-
+	/* apply options to new contexts (also default context being created) */
+	if (ctx || !usbi_default_context) {
 		for (enum libusb_option option = 0 ; option < LIBUSB_OPTION_MAX ; option++) {
 			if (LIBUSB_OPTION_LOG_LEVEL == option || !default_context_options[option].is_set) {
 				continue;
@@ -2332,6 +2328,13 @@
 		}
 	}
 
+	/* default context must be initialized before calling usbi_dbg */
+	if (!ctx) {
+		usbi_default_context = _ctx;
+		default_context_refcnt = 1;
+		usbi_dbg(usbi_default_context, "created default context");
+	}
+
 	usbi_dbg(_ctx, "libusb v%u.%u.%u.%u%s", libusb_version_internal.major, libusb_version_internal.minor,
 		libusb_version_internal.micro, libusb_version_internal.nano, libusb_version_internal.rc);
 
@@ -2353,7 +2356,6 @@
 			goto err_io_exit;
 	}
 
-
 	if (ctx)
 		*ctx = _ctx;
 
diff --git a/libusb/version_nano.h b/libusb/version_nano.h
index 9a3d393..af4599a 100644
--- a/libusb/version_nano.h
+++ b/libusb/version_nano.h
@@ -1 +1 @@
-#define LIBUSB_NANO 11666
+#define LIBUSB_NANO 11667