treewide: isArm -> isAarch32

Following legacy packing conventions, `isArm` was defined just for
32-bit ARM instruction set. This is confusing to non packagers though,
because Aarch64 is an ARM instruction set.

The official ARM overview for ARMv8[1] is surprisingly not confusing,
given the overall state of affairs for ARM naming conventions, and
offers us a solution. It divides the nomenclature into three levels:

```
ISA:             ARMv8   {-A, -R, -M}
                 /    \
Mode:     Aarch32     Aarch64
             |         /   \
Encoding:   A64      A32   T32
```

At the top is the overall v8 instruction set archicture. Second are the
two modes, defined by bitwidth but differing in other semantics too, and
buttom are the encodings, (hopefully?) isomorphic if they encode the
same mode.

The 32 bit encodings are mostly backwards compatible with previous
non-Thumb and Thumb encodings, and if so we can pun the mode names to
instead mean "sets of compatable or isomorphic encodings", and then
voilà we have nice names for 32-bit and 64-bit arm instruction sets
which do not use the word ARM so as to not confused either laymen or
experienced ARM packages.

[1]: https://developer.arm.com/products/architecture/a-profile

(cherry picked from commit ba52ae50488de85a9cf60a3a04f1c9ca7122ec74)

1 files changed, 7 insertions, 7 deletions

diff --git a/pkgs/development/libraries/ffmpeg/generic.nix b/pkgs/development/libraries/ffmpeg/generic.nix
index 985f328a22dd..4a05eab87bd7 100644
--- a/pkgs/development/libraries/ffmpeg/generic.nix
+++ b/pkgs/development/libraries/ffmpeg/generic.nix
@@ -7,8 +7,8 @@
 # Build options
 , runtimeCpuDetectBuild ? true # Detect CPU capabilities at runtime
 , multithreadBuild ? true # Multithreading via pthreads/win32 threads
-, sdlSupport ? !stdenv.isArm, SDL ? null, SDL2 ? null
-, vdpauSupport ? !stdenv.isArm, libvdpau ? null
+, sdlSupport ? !stdenv.isAarch32, SDL ? null, SDL2 ? null
+, vdpauSupport ? !stdenv.isAarch32, libvdpau ? null
 # Developer options
 , debugDeveloper ? false
 , optimizationsDeveloper ? true
@@ -42,7 +42,7 @@
  */
 
 let
-  inherit (stdenv) icCygwin isDarwin isFreeBSD isLinux isArm;
+  inherit (stdenv) icCygwin isDarwin isFreeBSD isLinux isAarch32;
   inherit (stdenv.lib) optional optionals enableFeature;
 
   cmpVer = builtins.compareVersions;
@@ -55,9 +55,9 @@ let
   verFix = withoutFix: fixVer: withFix: if reqMatch fixVer then withFix else withoutFix;
 
   # Disable dependency that needs fixes before it will work on Darwin or Arm
-  disDarwinOrArmFix = origArg: minVer: fixArg: if ((isDarwin || isArm) && reqMin minVer) then fixArg else origArg;
+  disDarwinOrArmFix = origArg: minVer: fixArg: if ((isDarwin || isAarch32) && reqMin minVer) then fixArg else origArg;
 
-  vaapiSupport = reqMin "0.6" && ((isLinux || isFreeBSD) && !isArm);
+  vaapiSupport = reqMin "0.6" && ((isLinux || isFreeBSD) && !isAarch32);
 in
 
 assert openglSupport -> libGLU_combined != null;
@@ -153,8 +153,8 @@ stdenv.mkDerivation rec {
     bzip2 fontconfig freetype gnutls libiconv lame libass libogg libtheora
     libvdpau libvorbis lzma soxr x264 x265 xvidcore zlib libopus
   ] ++ optional openglSupport libGLU_combined
-    ++ optionals (!isDarwin && !isArm) [ libvpx libpulseaudio ] # Need to be fixed on Darwin and ARM
-    ++ optional ((isLinux || isFreeBSD) && !isArm) libva
+    ++ optionals (!isDarwin && !isAarch32) [ libvpx libpulseaudio ] # Need to be fixed on Darwin and ARM
+    ++ optional ((isLinux || isFreeBSD) && !isAarch32) libva
     ++ optional isLinux alsaLib
     ++ optionals isDarwin darwinFrameworks
     ++ optional vdpauSupport libvdpau