diff --git a/doc/doc-support/lib-function-docs.nix b/doc/doc-support/lib-function-docs.nix
index 61671bd39059..51b4601975c3 100644
--- a/doc/doc-support/lib-function-docs.nix
+++ b/doc/doc-support/lib-function-docs.nix
@@ -95,7 +95,7 @@ stdenvNoCC.mkDerivation {
     fileset = ../../lib;
   };
 
-  buildInputs = [
+  nativeBuildInputs = [
     nixdoc
     nix
   ];
diff --git a/doc/tests/manpage-urls.nix b/doc/tests/manpage-urls.nix
index 214c23616009..913aebe4ebe8 100644
--- a/doc/tests/manpage-urls.nix
+++ b/doc/tests/manpage-urls.nix
@@ -17,7 +17,7 @@ invalidateFetcherByDrvHash (
     {
       nativeBuildInputs = [
         cacert
-        (python3.withPackages (p: [
+        (python3.pythonOnBuildForHost.withPackages (p: [
           p.aiohttp
           p.rich
           p.structlog
diff --git a/lib/tests/release.nix b/lib/tests/release.nix
index 5334498d0844..d83c15c511fa 100644
--- a/lib/tests/release.nix
+++ b/lib/tests/release.nix
@@ -1,18 +1,23 @@
 { # The pkgs used for dependencies for the testing itself
   # Don't test properties of pkgs.lib, but rather the lib in the parent directory
   pkgs ? import ../.. {} // { lib = throw "pkgs.lib accessed, but the lib tests should use nixpkgs' lib path directly!"; },
+  # For testing someone may edit impure.nix to return cross pkgs, use `pkgsBuildBuild` directly so everything here works.
+  pkgsBB ? pkgs.pkgsBuildBuild,
   nix ? pkgs-nixVersions.stable,
   nixVersions ? [ pkgs-nixVersions.minimum nix pkgs-nixVersions.latest ],
-  pkgs-nixVersions ? import ./nix-for-tests.nix { inherit pkgs; },
+  pkgs-nixVersions ? import ./nix-for-tests.nix { pkgs = pkgsBB; },
 }:
 
 let
   lib = import ../.;
   testWithNix = nix:
-    import ./test-with-nix.nix { inherit lib nix pkgs; };
+    import ./test-with-nix.nix {
+      inherit lib nix;
+      pkgs = pkgsBB;
+    };
 
 in
-  pkgs.symlinkJoin {
+  pkgsBB.symlinkJoin {
     name = "nixpkgs-lib-tests";
     paths = map testWithNix nixVersions;
   }
diff --git a/pkgs/applications/networking/cluster/k3s/builder.nix b/pkgs/applications/networking/cluster/k3s/builder.nix
index 551aef8d8ae2..2e0a4f5fec3d 100644
--- a/pkgs/applications/networking/cluster/k3s/builder.nix
+++ b/pkgs/applications/networking/cluster/k3s/builder.nix
@@ -138,7 +138,7 @@ let
     s:
     mutFirstChar lib.toLower (lib.concatMapStrings (mutFirstChar lib.toUpper) (lib.splitString "-" s));
 
-  # finds the images archive for the desired architecture, aborts in case no suitable archive is found
+  # finds the images archive for the desired architecture, throws in case no suitable archive is found
   findImagesArchive =
     arch:
     let
@@ -146,17 +146,17 @@ let
     in
     lib.findFirst (
       n: lib.hasInfix arch n
-    ) (abort "k3s: no airgap images for ${arch} available") imagesVersionsNames;
+    ) (throw "k3s: no airgap images for ${arch} available") imagesVersionsNames;
 
   # a shortcut that provides the images archive for the host platform. Currently only supports
-  # aarch64 (arm64) and x86_64 (amd64), aborts on other architectures.
+  # aarch64 (arm64) and x86_64 (amd64), throws on other architectures.
   airgapImages = fetchurl (
     if stdenv.hostPlatform.isAarch64 then
       imagesVersions.${findImagesArchive "arm64"}
     else if stdenv.hostPlatform.isx86_64 then
       imagesVersions.${findImagesArchive "amd64"}
     else
-      abort "k3s: airgap images cannot be found automatically for architecture ${stdenv.hostPlatform.linuxArch}, consider using an image archive with an explicit architecture."
+      throw "k3s: airgap images cannot be found automatically for architecture ${stdenv.hostPlatform.linuxArch}, consider using an image archive with an explicit architecture."
   );
 
   # so, k3s is a complicated thing to package
diff --git a/pkgs/by-name/de/debase/package.nix b/pkgs/by-name/de/debase/package.nix
index 1b300f1e21de..70be9b81eed6 100644
--- a/pkgs/by-name/de/debase/package.nix
+++ b/pkgs/by-name/de/debase/package.nix
@@ -72,7 +72,7 @@ stdenv.mkDerivation rec {
       else if stdenv.hostPlatform.isAarch64 then
         "arm64"
       else
-        abort "unsupported system: ${stdenv.system}"
+        throw "unsupported system: ${stdenv.system}"
     }"
   ];
 
diff --git a/pkgs/by-name/fr/frr/package.nix b/pkgs/by-name/fr/frr/package.nix
index 29f2d42d28f8..bc96316e7111 100644
--- a/pkgs/by-name/fr/frr/package.nix
+++ b/pkgs/by-name/fr/frr/package.nix
@@ -33,15 +33,9 @@
 , nettools
 , nixosTests
 
-# FRR's configure.ac gets SNMP options by executing net-snmp-config on the build host
-# This leads to compilation errors when cross compiling.
-# E.g. net-snmp-config for x86_64 does not return the ARM64 paths.
-#
-#   SNMP_LIBS="`${NETSNMP_CONFIG} --agent-libs`"
-#   SNMP_CFLAGS="`${NETSNMP_CONFIG} --base-cflags`"
-, snmpSupport ? stdenv.buildPlatform.canExecute stdenv.hostPlatform
 
-# other general options besides snmp support
+# general options
+, snmpSupport ? true
 , rpkiSupport ? true
 , numMultipath ? 64
 , watchfrrSupport ? true
@@ -81,9 +75,6 @@
 , ospfApi ? true
 }:
 
-lib.warnIf (!(stdenv.buildPlatform.canExecute stdenv.hostPlatform))
-  "cannot enable SNMP support due to cross-compilation issues with net-snmp-config"
-
 stdenv.mkDerivation (finalAttrs: {
   pname = "frr";
   version = "10.1";
@@ -194,6 +185,9 @@ stdenv.mkDerivation (finalAttrs: {
     (lib.strings.enableFeature ospfApi "ospfapi")
     # Cumulus options
     (lib.strings.enableFeature cumulusSupport "cumulus")
+  ] ++ lib.optionals snmpSupport [
+    # Used during build for paths, `dev` has build shebangs so can be run during build.
+    "NETSNMP_CONFIG=${lib.getDev net-snmp}/bin/net-snmp-config"
   ];
 
   postPatch = ''
diff --git a/pkgs/by-name/ni/nim-unwrapped-2_2/package.nix b/pkgs/by-name/ni/nim-unwrapped-2_2/package.nix
index 311c0f5b9d80..41307f320271 100644
--- a/pkgs/by-name/ni/nim-unwrapped-2_2/package.nix
+++ b/pkgs/by-name/ni/nim-unwrapped-2_2/package.nix
@@ -45,7 +45,7 @@ let
     else if isx86_64 then
       "amd64"
     else
-      abort "no Nim CPU support known for ${config}";
+      throw "no Nim CPU support known for ${config}";
 
   parseOs =
     platform:
@@ -72,7 +72,7 @@ let
     else if isiOS then
       "iOS"
     else
-      abort "no Nim OS support known for ${config}";
+      throw "no Nim OS support known for ${config}";
 
   parsePlatform = p: {
     cpu = parseCpu p;
diff --git a/pkgs/by-name/re/reposilite/plugins.nix b/pkgs/by-name/re/reposilite/plugins.nix
index 7fbae996b0ec..a64baf95f661 100644
--- a/pkgs/by-name/re/reposilite/plugins.nix
+++ b/pkgs/by-name/re/reposilite/plugins.nix
@@ -3,7 +3,7 @@
   makeScopeWithSplicing',
 }:
 makeScopeWithSplicing' {
-  otherSplices = generateSplicesForMkScope;
+  otherSplices = generateSplicesForMkScope "reposilitePlugins";
   f =
     self:
     {
diff --git a/pkgs/by-name/sa/saleae-logic/package.nix b/pkgs/by-name/sa/saleae-logic/package.nix
index 27b01dc5ffe1..7d1a95418e1a 100644
--- a/pkgs/by-name/sa/saleae-logic/package.nix
+++ b/pkgs/by-name/sa/saleae-logic/package.nix
@@ -22,8 +22,6 @@ let
 
 in
 
-assert stdenv.hostPlatform.system == "x86_64-linux";
-
 stdenv.mkDerivation rec {
   pname = "saleae-logic";
   version = "1.2.18";
@@ -92,7 +90,7 @@ stdenv.mkDerivation rec {
     homepage = "https://www.saleae.com/";
     sourceProvenance = with sourceTypes; [ binaryNativeCode ];
     license = licenses.unfree;
-    platforms = platforms.linux;
+    platforms = intersectLists platforms.x86_64 platforms.linux;
     maintainers = [ maintainers.bjornfor ];
   };
 }
diff --git a/pkgs/by-name/vi/virtual-ans/package.nix b/pkgs/by-name/vi/virtual-ans/package.nix
index 4a7467da125d..e71bc00e3042 100644
--- a/pkgs/by-name/vi/virtual-ans/package.nix
+++ b/pkgs/by-name/vi/virtual-ans/package.nix
@@ -46,7 +46,7 @@ stdenv.mkDerivation rec {
   startScript = if stdenv.hostPlatform.isx86_32 then "START_LINUX_X86"
     else        if stdenv.hostPlatform.isx86_64 then "START_LINUX_X86_64"
     #else        if stdenv.hostPlatform.isDarwin then "START_MACOS.app" # disabled because I cannot test on Darwin
-    else abort "Unsupported platform: ${stdenv.hostPlatform.linuxArch}.";
+    else throw "Unsupported platform: ${stdenv.hostPlatform.linuxArch}.";
 
   linuxExecutable = if stdenv.hostPlatform.isx86_32 then "pixilang_linux_x86"
     else            if stdenv.hostPlatform.isx86_64 then "pixilang_linux_x86_64"
diff --git a/pkgs/development/compilers/swift/compiler/default.nix b/pkgs/development/compilers/swift/compiler/default.nix
index 8e8cf798db4f..b8a415900322 100644
--- a/pkgs/development/compilers/swift/compiler/default.nix
+++ b/pkgs/development/compilers/swift/compiler/default.nix
@@ -541,7 +541,7 @@ in stdenv.mkDerivation {
     ";
     buildProject lldb llvm-project/lldb
 
-    ${lib.optionalString stdenv.hostPlatform.isDarwin ''
+    ${lib.optionalString stdenv.targetPlatform.isDarwin ''
     # Need to do a standalone build of concurrency for Darwin back deployment.
     # Based on: utils/swift_build_support/swift_build_support/products/backdeployconcurrency.py
     cmakeFlags="
diff --git a/pkgs/development/haskell-modules/generic-builder.nix b/pkgs/development/haskell-modules/generic-builder.nix
index 14afa3dfe6b4..7617bae86ece 100644
--- a/pkgs/development/haskell-modules/generic-builder.nix
+++ b/pkgs/development/haskell-modules/generic-builder.nix
@@ -802,7 +802,7 @@ stdenv.mkDerivation ({
         buildInputs =
           otherBuildInputsSystem;
         LANG = "en_US.UTF-8";
-        LOCALE_ARCHIVE = lib.optionalString (stdenv.hostPlatform.libc == "glibc") "${buildPackages.glibcLocales}/lib/locale/locale-archive";
+        LOCALE_ARCHIVE = lib.optionalString (stdenv.buildPlatform.libc == "glibc") "${buildPackages.glibcLocales}/lib/locale/locale-archive";
         "NIX_${ghcCommandCaps}" = "${ghcEnv}/bin/${ghcCommand}";
         "NIX_${ghcCommandCaps}PKG" = "${ghcEnv}/bin/${ghcCommand}-pkg";
         # TODO: is this still valid?
diff --git a/pkgs/development/interpreters/python/cpython/2.7/default.nix b/pkgs/development/interpreters/python/cpython/2.7/default.nix
index 7e926d682810..063a96dea0f1 100644
--- a/pkgs/development/interpreters/python/cpython/2.7/default.nix
+++ b/pkgs/development/interpreters/python/cpython/2.7/default.nix
@@ -204,7 +204,7 @@ let
   ] ++ lib.optionals stdenv.hostPlatform.isDarwin [
     "--disable-toolbox-glue"
   ] ++ lib.optionals (stdenv.hostPlatform != stdenv.buildPlatform) [
-    "PYTHON_FOR_BUILD=${lib.getBin buildPackages.python}/bin/python"
+    "PYTHON_FOR_BUILD=${lib.getBin buildPackages.python27}/bin/python"
     "ac_cv_buggy_getaddrinfo=no"
     # Assume little-endian IEEE 754 floating point when cross compiling
     "ac_cv_little_endian_double=yes"
@@ -239,7 +239,7 @@ let
   nativeBuildInputs =
     [ autoreconfHook ]
     ++ lib.optionals (stdenv.hostPlatform != stdenv.buildPlatform)
-      [ buildPackages.stdenv.cc buildPackages.python ];
+      [ buildPackages.stdenv.cc buildPackages.python27 ];
 
   mkPaths = paths: {
     C_INCLUDE_PATH = lib.makeSearchPathOutput "dev" "include" paths;
diff --git a/pkgs/test/stdenv/gcc-stageCompare.nix b/pkgs/test/stdenv/gcc-stageCompare.nix
index e5c2ed5921b3..c4a0179fb846 100644
--- a/pkgs/test/stdenv/gcc-stageCompare.nix
+++ b/pkgs/test/stdenv/gcc-stageCompare.nix
@@ -14,6 +14,7 @@
 }:
 
 assert stdenv.cc.isGNU;
+
 with pkgs;
 # rebuild gcc using the "final" stdenv
 let gcc-stageCompare = (gcc-unwrapped.override {
@@ -25,7 +26,9 @@ let gcc-stageCompare = (gcc-unwrapped.override {
     }).overrideAttrs(_: {
       NIX_OUTPATH_USED_AS_RANDOM_SEED = stdenv.cc.cc.out;
     });
-in (runCommand "gcc-stageCompare" {} ''
+in
+assert lib.assertMsg (gcc-stageCompare ? checksum) "tests-stdenv-gcc-stageCompare: No `checksum` output in `gcc-stageCompare` see conditional in `gcc/common/checksum.nix`";
+(runCommand "gcc-stageCompare" {} ''
   diff -sr ${pkgs.gcc-unwrapped.checksum}/checksums ${gcc-stageCompare.checksum}/checksums && touch $out
 '').overrideAttrs (a: {
   meta = (a.meta or { }) // { platforms = lib.platforms.linux; };