gnu: orc: Fix broken header file.

* gnu/packages/patches/orc-typedef-enum.patch: New file.
* gnu/local.mk (dist_patch_DATA): Adjust accordingly.
* gnu/packages/gstreamer.scm (orc)[source](patches): New field.

gnu/local.mk

@@ -1181,6 +1181,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/openssl-c-rehash-in.patch		\
   %D%/packages/patches/openssl-CVE-2019-1559.patch		\
   %D%/packages/patches/open-zwave-hidapi.patch			\
+  %D%/packages/patches/orc-typedef-enum.patch			\
   %D%/packages/patches/orpheus-cast-errors-and-includes.patch	\
   %D%/packages/patches/osip-CVE-2017-7853.patch			\
   %D%/packages/patches/ots-no-include-missing-file.patch	\

gnu/packages/gstreamer.scm

@@ -74,6 +74,7 @@ (define-public orc
               (method url-fetch)
               (uri (string-append "https://gstreamer.freedesktop.org/data/src/"
                                   "orc/orc-" version ".tar.xz"))
+              (patches (search-patches "orc-typedef-enum.patch"))
               (sha256
                (base32
                 "0wj93im7i8a6546q2r8sp39yjfbxflkc0ygb0b8iqsd58qhvjhds"))))

gnu/packages/patches/orc-typedef-enum.patch

@@ -0,0 +1,17 @@
+Orc 0.4.30 has a bug that causes duplicate symbols due to a missing typedef.
+
+Taken from upstream:
+https://gitlab.freedesktop.org/gstreamer/orc/merge_requests/32
+
+diff --git a/orc/orctarget.h b/orc/orctarget.h
+--- a/orc/orctarget.h
++++ b/orc/orctarget.h
+@@ -19,7 +19,7 @@ enum {
+   ORC_TARGET_FAST_DENORMAL = (1<<31)
+ };
+ 
+-enum {
++typedef enum {
+   ORC_TARGET_POWERPC_64BIT = (1<<0),
+   ORC_TARGET_POWERPC_LE = (1<<1),
+   ORC_TARGET_POWERPC_ALTIVEC = (1<<2),