gnu: x265: Fix building on armhf-linux.

* gnu/packages/video.scm (x265)[patches]: Add patch.
[arguments]: Add a configure-flag to disable assembly. Adjust a custom
phase to recognize armv8 as 32-bit arm when masquerading as armhf-linux.

gnu/local.mk

@@ -1243,6 +1243,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/wpa-supplicant-fix-zeroed-keys.patch	\
   %D%/packages/patches/wpa-supplicant-fix-nonce-reuse.patch	\
   %D%/packages/patches/wpa-supplicant-krack-followups.patch	\
+  %D%/packages/patches/x265-arm-flags.patch			\
   %D%/packages/patches/x265-detect512-all-arches.patch		\
   %D%/packages/patches/xboing-CVE-2004-0149.patch		\
   %D%/packages/patches/xf86-video-ark-remove-mibstore.patch	\

gnu/packages/patches/x265-arm-flags.patch

@@ -0,0 +1,36 @@
+https://sources.debian.org/src/x265/2.9-3/debian/patches/0001-Fix-arm-flags.patch/
+
+From: Sebastian Ramacher <sramacher@debian.org>
+Date: Wed, 26 Apr 2017 22:05:06 +0200
+Subject: Fix arm* flags
+
+---
+ source/CMakeLists.txt | 6 +-----
+ 1 file changed, 1 insertion(+), 5 deletions(-)
+
+diff --git a/source/CMakeLists.txt b/source/CMakeLists.txt
+index 33b6523..25aecbb 100644
+--- a/source/CMakeLists.txt
++++ b/source/CMakeLists.txt
+@@ -72,7 +72,7 @@ elseif(ARMMATCH GREATER "-1")
+     endif()
+     message(STATUS "Detected ARM target processor")
+     set(ARM 1)
+-    add_definitions(-DX265_ARCH_ARM=1 -DHAVE_ARMV6=1)
++    # add_definitions(-DX265_ARCH_ARM=1 -DHAVE_ARMV6=1)
+ else()
+     message(STATUS "CMAKE_SYSTEM_PROCESSOR value `${CMAKE_SYSTEM_PROCESSOR}` is unknown")
+     message(STATUS "Please add this value near ${CMAKE_CURRENT_LIST_FILE}:${CMAKE_CURRENT_LIST_LINE}")
+@@ -230,12 +230,8 @@ if(GCC)
+     if(ARM AND CROSS_COMPILE_ARM)
+         set(ARM_ARGS -march=armv6 -mfloat-abi=soft -mfpu=vfp -marm -fPIC)
+     elseif(ARM)
+-        find_package(Neon)
+         if(CPU_HAS_NEON)
+-            set(ARM_ARGS -mcpu=native -mfloat-abi=hard -mfpu=neon -marm -fPIC)
+             add_definitions(-DHAVE_NEON)
+-        else()
+-            set(ARM_ARGS -mcpu=native -mfloat-abi=hard -mfpu=vfp -marm)
+         endif()
+     endif()
+     add_definitions(${ARM_ARGS})

gnu/packages/video.scm

@@ -405,7 +405,8 @@ and creating Matroska files from other media files (@code{mkvmerge}).")
         (sha256
          (base32
           "090hp4216isis8q5gb7bwzia8rfyzni54z21jnwm97x3hiy6ibpb"))
-        (patches (search-patches "x265-detect512-all-arches.patch"))
+        (patches (search-patches "x265-arm-flags.patch"
+                                 "x265-detect512-all-arches.patch"))
         (modules '((guix build utils)))
         (snippet '(begin
                     (delete-file-recursively "source/compat/getopt")
@@ -416,6 +417,10 @@ and creating Matroska files from other media files (@code{mkvmerge}).")
        #:configure-flags
          ;; Ensure position independent code for everyone.
          (list "-DENABLE_PIC=TRUE"
+               ,@(if (string-prefix? "armhf" (or (%current-system)
+                                                 (%current-target-system)))
+                     '("-DENABLE_ASSEMBLY=OFF")
+                     '())
                (string-append "-DCMAKE_INSTALL_PREFIX="
                               (assoc-ref %outputs "out")))
        #:phases
@@ -424,6 +429,9 @@ and creating Matroska files from other media files (@code{mkvmerge}).")
            (lambda _
              (delete-file-recursively "build")
              (chdir "source")
+             ;; recognize armv8 in 32-bit mode as ARM
+             (substitute* "CMakeLists.txt"
+              (("armv6l") "armv8l"))
              #t))
          (add-before 'configure 'build-12-bit
            (lambda* (#:key (configure-flags '()) #:allow-other-keys)