gnu: libffi: Fix builds on Alpha.

* gnu/packages/patches/libffi-3.2.1-complex_alpha.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/libffi.scm (libffi)[source]: Use it.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

gnu/local.mk

@@ -697,6 +697,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/libevent-2.1-skip-failing-test.patch	\
   %D%/packages/patches/libextractor-ffmpeg-3.patch		\
   %D%/packages/patches/libgit2-use-after-free.patch		\
+  %D%/packages/patches/libffi-3.2.1-complex-alpha.patch		\
   %D%/packages/patches/libjxr-fix-function-signature.patch	\
   %D%/packages/patches/libjxr-fix-typos.patch			\
   %D%/packages/patches/liboop-mips64-deplibs-fix.patch		\

gnu/packages/libffi.scm

@@ -42,7 +42,8 @@
                              name "-" version ".tar.gz"))
              (sha256
               (base32
-               "0dya49bnhianl0r65m65xndz6ls2jn1xngyn72gd28ls3n7bnvnh"))))
+               "0dya49bnhianl0r65m65xndz6ls2jn1xngyn72gd28ls3n7bnvnh"))
+             (patches (search-patches "libffi-3.2.1-complex-alpha.patch"))))
     (build-system gnu-build-system)
     (arguments `(#:phases (alist-cons-after 'install 'post-install
                                             ,post-install-phase

gnu/packages/patches/libffi-3.2.1-complex-alpha.patch

@@ -0,0 +1,28 @@
+The patch fixes build failure of form:
+     ../src/alpha/osf.S:298:2: error: #error "osf.S out of sync with ffi.h"
+Upstream fixed the bug in a more invasive way
+but didn't have releases since 3.2.1.
+
+The patch is taken from Gentoo:
+https://gitweb.gentoo.org/repo/gentoo.git/tree/dev-libs/libffi/files/libffi-3.2.1-complex_alpha.patch
+
+--- libffi-3.2.1/src/alpha/osf.S	2015-01-16 10:46:15.000000000 +0100
++++ libffi-3.2.1/src/alpha/osf.S	2015-01-16 10:46:24.000000000 +0100
+@@ -279,6 +279,7 @@
+ 	.gprel32 $load_64	# FFI_TYPE_SINT64
+ 	.gprel32 $load_none	# FFI_TYPE_STRUCT
+ 	.gprel32 $load_64	# FFI_TYPE_POINTER
++	.gprel32 $load_none	# FFI_TYPE_COMPLEX
+ 
+ /* Assert that the table above is in sync with ffi.h.  */
+ 
+@@ -294,7 +295,8 @@
+ 	|| FFI_TYPE_SINT64 != 12	\
+ 	|| FFI_TYPE_STRUCT != 13	\
+ 	|| FFI_TYPE_POINTER != 14	\
+-	|| FFI_TYPE_LAST != 14
++	|| FFI_TYPE_COMPLEX != 15       \
++	|| FFI_TYPE_LAST != 15
+ #error "osf.S out of sync with ffi.h"
+ #endif
+