gnu: x265: Update to 3.4.

* gnu/packages/patches/x265-arm-flags.patch: Update patch.
* gnu/packages/video.scm (x265): Update to 3.4.
[arguments]: Remove obsolete substitution.  Disable the newly-added assembly
optimizations on AArch64, as they are not implemented for all targets we build.

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

@@ -1,4 +1,7 @@
-https://sources.debian.org/src/x265/2.9-3/debian/patches/0001-Fix-arm-flags.patch/
+Fix build flags for ARMv7.
+
+Taken from Debian:
+https://salsa.debian.org/multimedia-team/x265/-/blob/master/debian/patches/0001-Fix-arm-flags.patch
 
 From: Sebastian Ramacher <sramacher@debian.org>
 Date: Wed, 26 Apr 2017 22:05:06 +0200
@@ -9,23 +12,20 @@ Subject: Fix arm* flags
  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")
+@@ -77,7 +77,7 @@ elseif(ARMMATCH GREATER "-1")
-     endif()
+         add_definitions(-DX265_ARCH_ARM=1 -DX265_ARCH_ARM64=1 -DHAVE_ARMV6=0)
+     else()
          message(STATUS "Detected ARM target processor")
-     set(ARM 1)
+-        add_definitions(-DX265_ARCH_ARM=1 -DX265_ARCH_ARM64=0 -DHAVE_ARMV6=1)
--    add_definitions(-DX265_ARCH_ARM=1 -DHAVE_ARMV6=1)
++        add_definitions(-DX265_ARCH_ARM=1)
-+    # add_definitions(-DX265_ARCH_ARM=1 -DHAVE_ARMV6=1)
+     endif()
  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}")
+@@ -252,10 +252,7 @@ if(GCC)
-@@ -230,12 +230,8 @@ if(GCC)
+         else()
-     if(ARM AND CROSS_COMPILE_ARM)
+             find_package(Neon)
-         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)
@@ -33,4 +33,4 @@ index 33b6523..25aecbb 100644
 -                set(ARM_ARGS -mcpu=native -mfloat-abi=hard -mfpu=vfp -marm)
              endif()
          endif()
-     add_definitions(${ARM_ARGS})
+     endif()

gnu/packages/video.scm

@@ -611,7 +611,7 @@ available.")
 (define-public x265
   (package
     (name "x265")
-    (version "3.3")
+    (version "3.4")
     (outputs '("out" "static"))
     (source
       (origin
@@ -621,7 +621,7 @@ available.")
                    (string-append "https://download.videolan.org/videolan/x265/"
                                   "x265_" version ".tar.gz")))
         (sha256
-         (base32 "170b61cgpcs5n35qps0p40dqs1q81vkgagzbs4zv7pzls6718vpj"))
+         (base32 "0wl62hfsdqpf3r3z3s6l9bz7pdb1rcik5ll00b3yaadplqipy162"))
         (patches (search-patches "x265-arm-flags.patch"))
         (modules '((guix build utils)))
         (snippet '(begin
@@ -638,8 +638,7 @@ available.")
        #:configure-flags
          ;; Ensure position independent code for everyone.
          (list "-DENABLE_PIC=TRUE"
-               ,@(if (string-prefix? "armhf" (or (%current-system)
+               ,@(if (target-arm?)
-                                                 (%current-target-system)))
                      '("-DENABLE_ASSEMBLY=OFF")
                      '())
                (string-append "-DCMAKE_INSTALL_PREFIX="
@@ -650,9 +649,6 @@ available.")
            (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)