treewide: Simplify some `doCheck` calls

In anticipation of what I outline in #33599, I only simplify exactly those
`doCheck`s which are equal to `hostPlatform != buildPlatform`. I also stick a
comment next to them so I can grep for them later.

pkgs/applications/editors/ed/default.nix

···
 
   nativeBuildInputs = [ lzip ];
 
-  doCheck = hostPlatform == buildPlatform;
+  doCheck = true; # not cross;
 
   meta = {
     description = "An implementation of the standard Unix editor";

pkgs/development/libraries/boehm-gc/default.nix

···
     [ "--enable-cplusplus" ]
     ++ lib.optional enableLargeConfig "--enable-large-config";
 
-  doCheck = stdenv.buildPlatform == stdenv.hostPlatform;
+  doCheck = true; # not cross;
 
   # Don't run the native `strip' when cross-compiling.
   dontStrip = hostPlatform != buildPlatform;

pkgs/development/libraries/expat/default.nix

···
 
   outputMan = "dev"; # tiny page for a dev tool
 
-  doCheck = stdenv.hostPlatform == stdenv.buildPlatform;
+  doCheck = true; # not cross;
 
   preCheck = ''
     patchShebangs ./run.sh

pkgs/development/libraries/gdbm/default.nix

···
     sha256 = "0lx201q20dvc70f8a3c9s7s18z15inlxvbffph97ngvrgnyjq9cx";
   };
 
-  doCheck = stdenv.buildPlatform == stdenv.hostPlatform;
+  doCheck = true; # not cross;
 
   # Linking static stubs on cygwin requires correct ordering.
   # Consider upstreaming this.

pkgs/development/libraries/gmp/6.x.nix

···
 { stdenv, fetchurl, m4, cxx ? true
 , buildPackages
-, buildPlatform, hostPlatform
 , withStatic ? false }:
 
 let inherit (stdenv.lib) optional optionalString; in
···
       configureFlagsArray+=("--build=$(./configfsf.guess)")
     '';
 
-  doCheck = buildPlatform == hostPlatform;
+  doCheck = true; # not cross;
 
   dontDisableStatic = withStatic;
 

pkgs/development/libraries/libjpeg-turbo/default.nix

···
 
   enableParallelBuilding = true;
 
-  doCheck = stdenv.buildPlatform == stdenv.hostPlatform;
+  doCheck = true; # not cross;
   checkTarget = "test";
 
   meta = with stdenv.lib; {

pkgs/development/libraries/libmpc/default.nix

···
 
   CFLAGS = "-I${gmp.dev}/include";
 
-  doCheck = hostPlatform == buildPlatform;
+  doCheck = true; # not cross;
 
   meta = {
     description = "Library for multiprecision complex arithmetic with exact rounding";

pkgs/development/libraries/libpng/default.nix

···
 
   # it's hard to cross-run tests and some check programs didn't compile anyway
   makeFlags = stdenv.lib.optional (!doCheck) "check_PROGRAMS=";
-  doCheck = hostPlatform == buildPlatform;
+  doCheck = true; # not cross;
 
   passthru = { inherit zlib; };
 

pkgs/development/libraries/libsigsegv/default.nix

···
 
   patches = if enableSigbusFix then [ ./sigbus_fix.patch ] else null;
 
-  doCheck = hostPlatform == buildPlatform;
+  doCheck = true; # not cross;
 
   meta = {
     homepage = http://www.gnu.org/software/libsigsegv/;

pkgs/development/libraries/libtiff/default.nix

···
 
   enableParallelBuilding = true;
 
-  doCheck = stdenv.buildPlatform == stdenv.hostPlatform;
+  doCheck = true; # not cross;
 
   meta = with stdenv.lib; {
     description = "Library and utilities for working with the TIFF image file format";

pkgs/development/libraries/lzo/default.nix

···
 
   enableParallelBuilding = true;
 
-  doCheck = stdenv.hostPlatform == stdenv.buildPlatform;
+  doCheck = true; # not cross;
 
   meta = with stdenv.lib; {
     description = "Real-time data (de)compression library";

pkgs/development/libraries/mpfr/default.nix

···
     stdenv.lib.optional hostPlatform.isSunOS "--disable-thread-safe" ++
     stdenv.lib.optional hostPlatform.is64bit "--with-pic";
 
-  doCheck = hostPlatform == buildPlatform;
+  doCheck = true; # not cross;
 
   enableParallelBuilding = true;
 

pkgs/tools/system/ddrescue/default.nix

···
 
   nativeBuildInputs = [ lzip ];
 
-  doCheck = hostPlatform == buildPlatform;
+  doCheck = true; # not cross;
   configureFlags = [ "CXX=${stdenv.cc.targetPrefix}c++" ];
 
   meta = with stdenv.lib; {

pkgs/tools/text/gnupatch/default.nix

···
     "ac_cv_func_strnlen_working=yes"
   ];
 
-  doCheck = hostPlatform == buildPlatform;
+  doCheck = true; # not cross;
 
   meta = {
     description = "GNU Patch, a program to apply differences to files";