--- a/build/build-clang/build-clang.py
+++ b/build/build-clang/build-clang.py
@@ -119,19 +119,16 @@ def install_libgcc(gcc_dir, clang_dir):
     clang_lib_dir = os.path.join(clang_dir, "lib", "gcc",
                                  "x86_64-unknown-linux-gnu",
                                  os.path.basename(libgcc_dir))
     mkdir_p(clang_lib_dir)
     copy_tree(libgcc_dir, clang_lib_dir)
     libgcc_dir = os.path.join(gcc_dir, "lib64")
     clang_lib_dir = os.path.join(clang_dir, "lib")
     copy_tree(libgcc_dir, clang_lib_dir)
-    libgcc_dir = os.path.join(gcc_dir, "lib32")
-    clang_lib_dir = os.path.join(clang_dir, "lib32")
-    copy_tree(libgcc_dir, clang_lib_dir)
     include_dir = os.path.join(gcc_dir, "include")
     clang_include_dir = os.path.join(clang_dir, "include")
     copy_tree(include_dir, clang_include_dir)
 
 
 def install_import_library(build_dir, clang_dir):
     shutil.copy2(os.path.join(build_dir, "lib", "clang.lib"),
                  os.path.join(clang_dir, "lib"))
@@ -292,17 +289,17 @@ def get_tool(config, key):
 #           * (nothing will be deleted here)
 #   share/
 #     clang/
 #       clang-format-diff.py
 #       clang-tidy-diff.py
 #       run-clang-tidy.py
 def prune_final_dir_for_clang_tidy(final_dir):
     # Make sure we only have what we expect.
-    dirs = ("bin", "include", "lib", "lib32", "libexec", "msbuild-bin", "share", "tools")
+    dirs = ("bin", "include", "lib", "libexec", "msbuild-bin", "share", "tools")
     for f in glob.glob("%s/*" % final_dir):
         if os.path.basename(f) not in dirs:
             raise Exception("Found unknown file %s in the final directory" % f)
         if not os.path.isdir(f):
             raise Exception("Expected %s to be a directory" % f)
 
     # In bin/, only keep clang-tidy and clang-apply-replacements. The last one
     # is used to auto-fix some of the issues detected by clang-tidy.

--- a/build/unix/mozconfig.linux
+++ b/build/unix/mozconfig.linux
@@ -2,21 +2,17 @@ if [ "x$IS_NIGHTLY" = "xyes" ]; then
   # Some nightlies (eg: Mulet) don't want these set.
   MOZ_AUTOMATION_UPDATE_PACKAGING=${MOZ_AUTOMATION_UPDATE_PACKAGING-1}
 fi
 
 . "$topsrcdir/build/mozconfig.common"
 
 TOOLTOOL_DIR=${TOOLTOOL_DIR:-$topsrcdir}
 
-if [ -n "$FORCE_GCC" ]; then
-    CC="$TOOLTOOL_DIR/gcc/bin/gcc"
-    CXX="$TOOLTOOL_DIR/gcc/bin/g++"
-else
-    CC="$TOOLTOOL_DIR/clang/bin/clang"
-    CXX="$TOOLTOOL_DIR/clang/bin/clang++"
-fi
+# We deal with valgrind builds here
+CC="$TOOLTOOL_DIR/gcc/bin/gcc"
+CXX="$TOOLTOOL_DIR/gcc/bin/g++"
 
 # We want to make sure we use binutils and other binaries in the tooltool
 # package.
 mk_add_options "export PATH=$TOOLTOOL_DIR/gcc/bin:$PATH"
 
 . "$topsrcdir/build/unix/mozconfig.stdcxx"

--- a/taskcluster/ci/build/linux.yml
+++ b/taskcluster/ci/build/linux.yml
@@ -99,18 +99,16 @@ linux64/pgo:
     attributes:
         enable-full-crashsymbols: true
     treeherder:
         platform: linux64/pgo
         symbol: B
     worker-type: aws-provisioner-v1/gecko-{level}-b-linux
     worker:
         max-run-time: 7200
-        env:
-            FORCE_GCC: '1'
     run:
         using: mozharness
         actions: [get-secrets build check-test update]
         options: [enable-pgo]
         config:
             - builds/releng_base_firefox.py
             - builds/releng_base_linux_64_builds.py
         script: "mozharness/scripts/fx_desktop_build.py"
@@ -133,17 +131,16 @@ linux64-fuzzing/debug:
     treeherder:
         platform: linux64/debug
         symbol: Bf
     worker-type: aws-provisioner-v1/gecko-{level}-b-linux
     worker:
         max-run-time: 3600
         env:
             PERFHERDER_EXTRA_OPTIONS: fuzzing
-            FORCE_GCC: '1'
     run:
         using: mozharness
         actions: [get-secrets build check-test update]
         config:
             - builds/releng_base_firefox.py
             - builds/releng_base_linux_64_builds.py
         script: "mozharness/scripts/fx_desktop_build.py"
         secrets: true
@@ -231,18 +228,16 @@ linux64-devedition-nightly/opt:
         job-name: linux64-opt
         type: nightly
     treeherder:
         platform: linux64-devedition/opt
         symbol: N
     worker-type: aws-provisioner-v1/gecko-{level}-b-linux
     worker:
         max-run-time: 7200
-        env:
-            FORCE_GCC: '1'
     run:
         using: mozharness
         actions: [get-secrets build check-test update]
         config:
             - builds/releng_base_firefox.py
             - builds/releng_base_linux_64_builds.py
             - taskcluster_nightly.py
         script: "mozharness/scripts/fx_desktop_build.py"
@@ -267,17 +262,16 @@ linux64-base-toolchains/opt:
     treeherder:
         platform: linux64/opt
         symbol: Bb
     worker-type: aws-provisioner-v1/gecko-{level}-b-linux
     worker:
         max-run-time: 7200
         env:
             PERFHERDER_EXTRA_OPTIONS: base-toolchains
-            FORCE_GCC: '1'
     run:
         using: mozharness
         actions: [get-secrets build check-test update]
         config:
             - builds/releng_base_firefox.py
             - builds/releng_base_linux_64_builds.py
         script: "mozharness/scripts/fx_desktop_build.py"
         secrets: true
@@ -298,17 +292,16 @@ linux64-base-toolchains/debug:
     treeherder:
         platform: linux64/debug
         symbol: Bb
     worker-type: aws-provisioner-v1/gecko-{level}-b-linux
     worker:
         max-run-time: 3600
         env:
             PERFHERDER_EXTRA_OPTIONS: base-toolchains
-            FORCE_GCC: '1'
     run:
         using: mozharness
         actions: [get-secrets build check-test update]
         config:
             - builds/releng_base_firefox.py
             - builds/releng_base_linux_64_builds.py
         script: "mozharness/scripts/fx_desktop_build.py"
         secrets: true
@@ -396,18 +389,16 @@ linux/pgo:
         enable-full-crashsymbols: true
     treeherder:
         platform: linux32/pgo
         symbol: B
     worker-type: aws-provisioner-v1/gecko-{level}-b-linux
     worker:
         docker-image: {in-tree: debian7-i386-build}
         max-run-time: 7200
-        env:
-            FORCE_GCC: '1'
     run:
         using: mozharness
         actions: [get-secrets build check-test update]
         options: [enable-pgo]
         config:
             - builds/releng_base_firefox.py
             - builds/releng_base_linux_32_builds.py
         script: "mozharness/scripts/fx_desktop_build.py"
@@ -505,18 +496,16 @@ linux-devedition-nightly/opt:
         type: nightly
     treeherder:
         platform: linux32-devedition/opt
         symbol: N
     worker-type: aws-provisioner-v1/gecko-{level}-b-linux
     worker:
         docker-image: {in-tree: debian7-i386-build}
         max-run-time: 7200
-        env:
-            FORCE_GCC: '1'
     run:
         using: mozharness
         actions: [get-secrets build check-test update]
         config:
             - builds/releng_base_firefox.py
             - builds/releng_base_linux_32_builds.py
             - taskcluster_nightly.py
         script: "mozharness/scripts/fx_desktop_build.py"
@@ -546,18 +535,16 @@ linux-nightly/opt:
         type: nightly
     treeherder:
         platform: linux32/opt
         symbol: N
     worker-type: aws-provisioner-v1/gecko-{level}-b-linux
     worker:
         docker-image: {in-tree: debian7-i386-build}
         max-run-time: 7200
-        env:
-            FORCE_GCC: '1'
     run:
         using: mozharness
         actions: [get-secrets build check-test update]
         config:
             - builds/releng_base_firefox.py
             - builds/releng_base_linux_32_builds.py
             - taskcluster_nightly.py
         script: "mozharness/scripts/fx_desktop_build.py"
@@ -815,18 +802,16 @@ linux64-nightly/opt:
         job-name: linux64-opt
         type: nightly
     treeherder:
         platform: linux64/opt
         symbol: N
     worker-type: aws-provisioner-v1/gecko-{level}-b-linux
     worker:
         max-run-time: 7200
-        env:
-            FORCE_GCC: '1'
     run:
         using: mozharness
         actions: [get-secrets build check-test update]
         config:
             - builds/releng_base_firefox.py
             - builds/releng_base_linux_64_builds.py
             - taskcluster_nightly.py
         script: "mozharness/scripts/fx_desktop_build.py"
@@ -1013,18 +998,16 @@ linux64-ccov/debug:
     treeherder:
         platform: linux64-ccov/debug
         symbol: B
         tier: 2
     run-on-projects: ['mozilla-central', 'try']
     worker-type: aws-provisioner-v1/gecko-{level}-b-linux
     worker:
         max-run-time: 7200
-        env:
-            FORCE_GCC: '1'
     run:
         using: mozharness
         actions: [get-secrets build check-test update]
         config:
             - builds/releng_base_firefox.py
             - builds/releng_base_linux_64_builds.py
         script: "mozharness/scripts/fx_desktop_build.py"
         secrets: true
@@ -1046,18 +1029,16 @@ linux64-ccov/opt:
     treeherder:
         platform: linux64-ccov/opt
         symbol: B
         tier: 2
     run-on-projects: ['mozilla-central', 'try']
     worker-type: aws-provisioner-v1/gecko-{level}-b-linux
     worker:
         max-run-time: 7200
-        env:
-            FORCE_GCC: '1'
     run:
         using: mozharness
         actions: [get-secrets build check-test update]
         config:
             - builds/releng_base_firefox.py
             - builds/releng_base_linux_64_builds.py
         script: "mozharness/scripts/fx_desktop_build.py"
         secrets: true

--- a/taskcluster/ci/valgrind/kind.yml
+++ b/taskcluster/ci/valgrind/kind.yml
@@ -26,17 +26,16 @@ jobs:
             kind: build
             tier: 1
         worker-type: aws-provisioner-v1/gecko-{level}-b-linux
         worker:
             docker-image: {in-tree: valgrind-build}
             max-run-time: 72000
             env:
                 PERFHERDER_EXTRA_OPTIONS: valgrind
-                FORCE_GCC: '1'
         run:
             using: mozharness
             actions: [get-secrets build valgrind-test]
             custom-build-variant-cfg: valgrind
             config:
                 - builds/releng_base_firefox.py
                 - builds/releng_base_linux_64_builds.py
             script: "mozharness/scripts/fx_desktop_build.py"