Fixes for C enums used in an API and the definition of the enum has not been parsed.

For D, this fixes a segfault in SWIG.

Java, C#, D, Go now produce code that compiles, although the definition of the
enum is needed in order to use the enum properly from the target language.

Examples/test-suite/common.mk

@@ -580,6 +580,7 @@ C_TEST_CASES += \
 	enums \
 	enum_forward \
 	enum_macro \
+	enum_missing \
 	extern_declaration \
 	funcptr \
 	function_typedef \

Examples/test-suite/enum_missing.i

@@ -0,0 +1,39 @@
+%module enum_missing
+
+// Test when SWIG does not parse the enum definition
+%{
+enum AVPixelFormat {
+    AV_PIX_FMT_NONE = -1,
+    AV_PIX_FMT_YUV420P
+};
+enum AVPixelFormat2 {
+    AV_PIX_FMT_NONE2 = -1,
+    AV_PIX_FMT_YUV420P2
+};
+
+%}
+
+%inline %{
+typedef struct AVCodecContext {
+  enum AVPixelFormat pix_fmt;
+  enum AVPixelFormat2 pix_fmt2;
+} AVCodecContext;
+
+enum AVPixelFormat global_fmt;
+enum AVPixelFormat2 global_fmt2;
+
+enum AVPixelFormat use_pixel_format(enum AVPixelFormat px) {
+  return px;
+}
+enum AVPixelFormat * use_pixel_format_ptr(enum AVPixelFormat *px) {
+  return px;
+}
+
+const enum AVPixelFormat2 use_pixel_format2(const enum AVPixelFormat2 px) {
+  return px;
+}
+const enum AVPixelFormat2 * use_pixel_format_ptr2(const enum AVPixelFormat2 *px) {
+  return px;
+}
+%}
+