diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index ec338f5b913c9..5892e16342abb 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -7113,67 +7113,51 @@ with pkgs;
 
   llvmPackages = recurseIntoAttrs llvmPackages_5;
 
-  llvmPackages_35 = callPackage ../development/compilers/llvm/3.5 ({
+  llvmPackages_35 = callPackage ../development/compilers/llvm/3.5 {
     isl = isl_0_14;
-  } // stdenv.lib.optionalAttrs (stdenv.cc.isGNU && stdenv.hostPlatform.isi686) {
-    stdenv = overrideCC stdenv buildPackages.gcc6;
-  });
+  };
 
-  llvmPackages_37 = callPackage ../development/compilers/llvm/3.7 ({
+  llvmPackages_37 = callPackage ../development/compilers/llvm/3.7 {
     inherit (stdenvAdapters) overrideCC;
     buildLlvmTools = buildPackages.llvmPackages_37.tools;
     targetLlvmLibraries = targetPackages.llvmPackages_37.libraries;
-  } // stdenv.lib.optionalAttrs (stdenv.cc.isGNU && stdenv.hostPlatform.isi686) {
-    stdenv = overrideCC stdenv buildPackages.gcc6;
-  });
+  };
 
-  llvmPackages_38 = callPackage ../development/compilers/llvm/3.8 ({
+  llvmPackages_38 = callPackage ../development/compilers/llvm/3.8 {
     inherit (stdenvAdapters) overrideCC;
     buildLlvmTools = buildPackages.llvmPackages_38.tools;
     targetLlvmLibraries = targetPackages.llvmPackages_38.libraries;
-  } // stdenv.lib.optionalAttrs (stdenv.cc.isGNU && stdenv.hostPlatform.isi686) {
-    stdenv = overrideCC stdenv buildPackages.gcc6;
-  });
+  };
 
-  llvmPackages_39 = callPackage ../development/compilers/llvm/3.9 ({
+  llvmPackages_39 = callPackage ../development/compilers/llvm/3.9 {
     inherit (stdenvAdapters) overrideCC;
     buildLlvmTools = buildPackages.llvmPackages_39.tools;
     targetLlvmLibraries = targetPackages.llvmPackages_39.libraries;
-  } // stdenv.lib.optionalAttrs (stdenv.cc.isGNU && stdenv.hostPlatform.isi686) {
-    stdenv = overrideCC stdenv buildPackages.gcc6;
-  });
+  };
 
-  llvmPackages_4 = callPackage ../development/compilers/llvm/4 ({
+  llvmPackages_4 = callPackage ../development/compilers/llvm/4 {
     inherit (stdenvAdapters) overrideCC;
     buildLlvmTools = buildPackages.llvmPackages_4.tools;
     targetLlvmLibraries = targetPackages.llvmPackages_4.libraries;
-  } // stdenv.lib.optionalAttrs (stdenv.cc.isGNU && stdenv.hostPlatform.isi686) {
-    stdenv = overrideCC stdenv buildPackages.gcc6;
-  });
+  };
 
-  llvmPackages_5 = callPackage ../development/compilers/llvm/5 ({
+  llvmPackages_5 = callPackage ../development/compilers/llvm/5 {
     inherit (stdenvAdapters) overrideCC;
     buildLlvmTools = buildPackages.llvmPackages_5.tools;
     targetLlvmLibraries = targetPackages.llvmPackages_5.libraries;
-  } // stdenv.lib.optionalAttrs (stdenv.cc.isGNU && stdenv.hostPlatform.isi686) {
-    stdenv = overrideCC stdenv buildPackages.gcc6; # with gcc-7: undefined reference to `__divmoddi4'
-  });
+  };
 
-  llvmPackages_6 = callPackage ../development/compilers/llvm/6 ({
+  llvmPackages_6 = callPackage ../development/compilers/llvm/6 {
     inherit (stdenvAdapters) overrideCC;
     buildLlvmTools = buildPackages.llvmPackages_6.tools;
     targetLlvmLibraries = targetPackages.llvmPackages_6.libraries;
-  } // stdenv.lib.optionalAttrs (stdenv.cc.isGNU && stdenv.hostPlatform.isi686) {
-    stdenv = overrideCC stdenv buildPackages.gcc6; # with gcc-7: undefined reference to `__divmoddi4'
-  });
+  };
 
-  llvmPackages_7 = callPackage ../development/compilers/llvm/7 ({
+  llvmPackages_7 = callPackage ../development/compilers/llvm/7 {
     inherit (stdenvAdapters) overrideCC;
     buildLlvmTools = buildPackages.llvmPackages_7.tools;
     targetLlvmLibraries = targetPackages.llvmPackages_7.libraries;
-  } // stdenv.lib.optionalAttrs (stdenv.cc.isGNU && stdenv.hostPlatform.isi686) {
-    stdenv = overrideCC stdenv buildPackages.gcc6; # with gcc-7: undefined reference to `__divmoddi4'
-  });
+  };
 
   manticore = callPackage ../development/compilers/manticore { };
 
@@ -7308,11 +7292,9 @@ with pkgs;
   };
 
   # For beta and nightly releases use the nixpkgs-mozilla overlay
-  rust = callPackage ../development/compilers/rust ({
+  rust = callPackage ../development/compilers/rust {
     inherit (darwin.apple_sdk.frameworks) CoreFoundation Security;
-  } // stdenv.lib.optionalAttrs (stdenv.cc.isGNU && stdenv.hostPlatform.isi686) {
-    stdenv = overrideCC stdenv gcc6; # with gcc-7: undefined reference to `__divmoddi4'
-  });
+  };
   inherit (rust) cargo rustc;
 
   buildRustCrate = callPackage ../build-support/rust/build-rust-crate { };
@@ -7911,11 +7893,9 @@ with pkgs;
     stdenv = gccStdenv;
   };
   spidermonkey_31 = callPackage ../development/interpreters/spidermonkey/31.nix { };
-  spidermonkey_38 = callPackage ../development/interpreters/spidermonkey/38.nix ({
+  spidermonkey_38 = callPackage ../development/interpreters/spidermonkey/38.nix {
     inherit (darwin) libobjc;
-  } // (stdenv.lib.optionalAttrs (stdenv.cc.isGNU && stdenv.hostPlatform.isi686) {
-      stdenv = overrideCC stdenv gcc6; # with gcc-7: undefined reference to `__divmoddi4'
-  }));
+  };
   spidermonkey_52 = callPackage ../development/interpreters/spidermonkey/52.nix { };
   spidermonkey = spidermonkey_31;
 
@@ -10087,22 +10067,15 @@ with pkgs;
 
   hyena = callPackage ../development/libraries/hyena { mono = mono4; };
 
-  icu58 = callPackage (import ../development/libraries/icu/58.nix fetchurl) ({
+  icu58 = callPackage (import ../development/libraries/icu/58.nix fetchurl) {
     nativeBuildRoot = buildPackages.icu58.override { buildRootOnly = true; };
-  } //
-    (stdenv.lib.optionalAttrs (stdenv.cc.isGNU && stdenv.hostPlatform.isi686) {
-      stdenv = overrideCC stdenv gcc6; # with gcc-7: undefined reference to `__divmoddi4'
-    }));
-  icu59 = callPackage ../development/libraries/icu/59.nix ({
+  };
+  icu59 = callPackage ../development/libraries/icu/59.nix {
     nativeBuildRoot = buildPackages.icu59.override { buildRootOnly = true; };
-  } // (stdenv.lib.optionalAttrs (stdenv.cc.isGNU && stdenv.hostPlatform.isi686) {
-      stdenv = overrideCC stdenv gcc6; # with gcc-7: undefined reference to `__divmoddi4'
-    }));
-  icu60 = callPackage ../development/libraries/icu/60.nix ({
+  };
+  icu60 = callPackage ../development/libraries/icu/60.nix {
     nativeBuildRoot = buildPackages.icu60.override { buildRootOnly = true; };
-  } // (stdenv.lib.optionalAttrs (stdenv.cc.isGNU && stdenv.hostPlatform.isi686) {
-      stdenv = overrideCC stdenv gcc6; # with gcc-7: undefined reference to `__divmoddi4'
-    }));
+  };
 
   icu = icu59;