diff --git a/pkgs/build-support/cc-wrapper/default.nix b/pkgs/build-support/cc-wrapper/default.nix
index ae4bdfd575b..5978d8665d0 100644
--- a/pkgs/build-support/cc-wrapper/default.nix
+++ b/pkgs/build-support/cc-wrapper/default.nix
@@ -238,7 +238,7 @@ stdenv.mkDerivation {
       # compile, because it uses "#include_next <limits.h>" to find the
       # limits.h file in ../includes-fixed. To remedy the problem,
       # another -idirafter is necessary to add that directory again.
-      echo "-B${libc_lib}/lib/ -idirafter ${libc_dev}/include -idirafter ${cc}/lib/gcc/*/*/include-fixed" > $out/nix-support/libc-cflags
+      echo "-B${libc_lib}/lib/ -idirafter ${libc_dev}/include ${optionalString isGNU "-idirafter ${cc}/lib/gcc/*/*/include-fixed"}" > $out/nix-support/libc-cflags
 
       echo "${libc_lib}" > $out/nix-support/orig-libc
       echo "${libc_dev}" > $out/nix-support/orig-libc-dev
diff --git a/pkgs/development/compilers/llvm/multi.nix b/pkgs/development/compilers/llvm/multi.nix
new file mode 100644
index 00000000000..0fa0eb3404d
--- /dev/null
+++ b/pkgs/development/compilers/llvm/multi.nix
@@ -0,0 +1,44 @@
+{ runCommand,
+clang,
+gcc64,
+gcc32,
+glibc_multi
+}:
+
+let
+  combine = basegcc: runCommand "combine-gcc-libc" {} ''
+    mkdir -p $out
+    cp -r ${basegcc.cc}/lib $out/lib
+
+    chmod u+rw -R $out/lib
+    cp -r ${basegcc.libc}/lib/* $(ls -d $out/lib/gcc/*/*)
+  '';
+  gcc_multi_sysroot = runCommand "gcc-multi-sysroot" {} ''
+    mkdir -p $out/lib/gcc
+
+    ln -s ${combine gcc64}/lib/gcc/* $out/lib/gcc/
+    ln -s ${combine gcc32}/lib/gcc/* $out/lib/gcc/
+    # XXX: This shouldn't be needed, clang just doesn't look for "i686-unknown"
+    ln -s $out/lib/gcc/i686-unknown-linux-gnu $out/lib/gcc/i686-pc-linux-gnu
+
+
+    # includes
+    ln -s ${glibc_multi.dev}/include $out/
+
+    # dynamic linkers
+    mkdir -p $out/lib/32
+    ln -s ${glibc_multi.out}/lib/ld-linux* $out/lib
+    ln -s ${glibc_multi.out}/lib/32/ld-linux* $out/lib/32/
+  '';
+
+  clangMulti = clang.override {
+    # Only used for providing expected structure re:dynamic linkers, AFAIK
+    # Most of the magic is done by setting the --gcc-toolchain option below
+    libc = gcc_multi_sysroot;
+
+    extraBuildCommands = ''
+      sed -e '$a --gcc-toolchain=${gcc_multi_sysroot}' -i $out/nix-support/libc-cflags
+    '';
+  };
+
+in clangMulti
diff --git a/pkgs/development/libraries/qt-4.x/4.8/default.nix b/pkgs/development/libraries/qt-4.x/4.8/default.nix
index a73f63bfb4b..a54860ff0ac 100644
--- a/pkgs/development/libraries/qt-4.x/4.8/default.nix
+++ b/pkgs/development/libraries/qt-4.x/4.8/default.nix
@@ -128,7 +128,7 @@ stdenv.mkDerivation rec {
 
   postConfigure = ''
     echo "applying patch ${./parallel-build.patch}"
-    patch -p1 -i ${./parallel-build.patch}
+    patch -p1 < ${./parallel-build.patch}
   '';
 
   prefixKey = "-prefix ";
diff --git a/pkgs/development/libraries/qt-4.x/4.8/parallel-build.patch b/pkgs/development/libraries/qt-4.x/4.8/parallel-build.patch
index d471bb2a665..5783543e844 100644
--- a/pkgs/development/libraries/qt-4.x/4.8/parallel-build.patch
+++ b/pkgs/development/libraries/qt-4.x/4.8/parallel-build.patch
@@ -1,6 +1,6 @@
 --- a/tools/designer/src/lib/Makefile
 +++ b/tools/designer/src/lib/Makefile
 @@ -7167,2 +7167,3 @@ compiler_moc_header_clean:
- 		.uic/release-shared/ui_qtgradientviewdialog.h \
-+		.uic/release-shared/ui_qtgradientview.h \
- 		../../../shared/qtgradienteditor/qtgradientviewdialog.h
+                .uic/release-shared/ui_qtgradientviewdialog.h \
++               .uic/release-shared/ui_qtgradientview.h \
+                ../../../shared/qtgradienteditor/qtgradientviewdialog.h
diff --git a/pkgs/test/cc-wrapper/multilib.nix b/pkgs/test/cc-wrapper/multilib.nix
new file mode 100644
index 00000000000..5ea50b5eb26
--- /dev/null
+++ b/pkgs/test/cc-wrapper/multilib.nix
@@ -0,0 +1,37 @@
+{ stdenv }:
+
+stdenv.mkDerivation {
+  name = "cc-multilib-test";
+
+  # XXX: "depend" on cc-wrapper test?
+
+  # TODO: Have tests report pointer size or something; ensure they are what we asked for
+  buildCommand = ''
+    NIX_DEBUG=1 $CC -v
+    NIX_DEBUG=1 $CXX -v
+
+    printf "checking whether compiler builds valid C binaries... " >&2
+    $CC -o cc-check ${./cc-main.c}
+    ./cc-check
+
+    printf "checking whether compiler builds valid 32bit C binaries... " >&2
+    $CC -m32 -o c32-check ${./cc-main.c}
+    ./c32-check
+
+    printf "checking whether compiler builds valid 64bit C binaries... " >&2
+    $CC -m64 -o c64-check ${./cc-main.c}
+    ./c64-check
+
+    printf "checking whether compiler builds valid 32bit C++ binaries... " >&2
+    $CXX -m32 -o cxx32-check ${./cxx-main.cc}
+    ./cxx32-check
+
+    printf "checking whether compiler builds valid 64bit C++ binaries... " >&2
+    $CXX -m64 -o cxx64-check ${./cxx-main.cc}
+    ./cxx64-check
+
+    touch $out
+  '';
+
+  meta.platforms = stdenv.lib.platforms.x86_64;
+}
diff --git a/pkgs/tools/networking/curl/default.nix b/pkgs/tools/networking/curl/default.nix
index 7f8d50b6d89..c356a307e3e 100644
--- a/pkgs/tools/networking/curl/default.nix
+++ b/pkgs/tools/networking/curl/default.nix
@@ -8,6 +8,7 @@
 , scpSupport ? false, libssh2 ? null
 , gssSupport ? false, gss ? null
 , c-aresSupport ? false, c-ares ? null
+, brotliSupport ? false, brotli ? null
 }:
 
 assert http2Support -> nghttp2 != null;
@@ -19,6 +20,7 @@ assert !(gnutlsSupport && sslSupport);
 assert gnutlsSupport -> gnutls != null;
 assert scpSupport -> libssh2 != null;
 assert c-aresSupport -> c-ares != null;
+assert brotliSupport -> brotli != null;
 
 stdenv.mkDerivation rec {
   name = "curl-7.57.0";
@@ -47,7 +49,8 @@ stdenv.mkDerivation rec {
     optional c-aresSupport c-ares ++
     optional sslSupport openssl ++
     optional gnutlsSupport gnutls ++
-    optional scpSupport libssh2;
+    optional scpSupport libssh2 ++
+    optional brotliSupport brotli;
 
   # for the second line see https://curl.haxx.se/mail/tracker-2014-03/0087.html
   preConfigure = ''
@@ -64,6 +67,7 @@ stdenv.mkDerivation rec {
       ( if ldapSupport then "--enable-ldap" else "--disable-ldap" )
       ( if ldapSupport then "--enable-ldaps" else "--disable-ldaps" )
       ( if idnSupport then "--with-libidn=${libidn.dev}" else "--without-libidn" )
+      ( if brotliSupport then "--with-brotli" else "--without-brotli" )
     ]
     ++ stdenv.lib.optional c-aresSupport "--enable-ares=${c-ares}"
     ++ stdenv.lib.optional gssSupport "--with-gssapi=${gss}";
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 2e90f94ab58..ed944759871 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -1639,6 +1639,7 @@ with pkgs;
     idnSupport = true;
     ldapSupport = true;
     gssSupport = true;
+    brotliSupport = true;
   };
 
   curl = callPackage ../tools/networking/curl rec {
@@ -5585,7 +5586,20 @@ with pkgs;
       '';
   }) else throw "Multilib ${cc.name} not supported on ‘${system}’";
 
+  wrapClangMulti = clang:
+    if system == "x86_64-linux" then
+      callPackages ../development/compilers/llvm/multi.nix {
+        inherit clang;
+        gcc32 = pkgsi686Linux.gcc;
+        gcc64 = pkgs.gcc;
+      }
+    else throw "Multilib ${clang.cc.name} not supported on '${system}'";
+
   gcc_multi = wrapCCMulti gcc;
+  clang_multi = wrapClangMulti clang;
+
+  gccMultiStdenv = overrideCC stdenv gcc_multi;
+  clangMultiStdenv = overrideCC stdenv clang_multi;
 
   gcc_debug = lowPrio (wrapCC (gcc.cc.override {
     stripped = false;
@@ -20077,6 +20091,9 @@ with pkgs;
     cc-wrapper-libcxx-5 = callPackage ../test/cc-wrapper { stdenv = llvmPackages_5.libcxxStdenv; };
     stdenv-inputs = callPackage ../test/stdenv-inputs { };
 
+    cc-multilib-gcc = callPackage ../test/cc-wrapper/multilib.nix { stdenv = gccMultiStdenv; };
+    cc-multilib-clang = callPackage ../test/cc-wrapper/multilib.nix { stdenv = clangMultiStdenv; };
+
     macOSSierraShared = callPackage ../test/macos-sierra-shared {};
   };
 
diff --git a/pkgs/top-level/release.nix b/pkgs/top-level/release.nix
index 8cbb7063b4e..201c3a38cf8 100644
--- a/pkgs/top-level/release.nix
+++ b/pkgs/top-level/release.nix
@@ -112,6 +112,8 @@ let
               jobs.tests.cc-wrapper-clang-39.x86_64-darwin
               jobs.tests.cc-wrapper-libcxx-39.x86_64-linux
               jobs.tests.cc-wrapper-libcxx-39.x86_64-darwin
+              jobs.tests.cc-multilib-gcc.x86_64-linux
+              jobs.tests.cc-multilib-clang.x86_64-linux
               jobs.tests.stdenv-inputs.x86_64-linux
               jobs.tests.stdenv-inputs.x86_64-darwin
               jobs.tests.macOSSierraShared.x86_64-darwin