diff --git a/.travis.yml b/.travis.yml
index 010665776..6e363fd79 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -54,7 +54,7 @@ after_success:
 after_script: set +e
 
 before_cache:
-  - docker history -q japaric/$TARGET:v0.1.10 |
+  - docker history -q japaric/$TARGET:v0.1.12 |
     grep -v \<missing\> |
     xargs docker save |
     gzip > $HOME/docker/$TARGET.tar.gz
diff --git a/docker/aarch64-unknown-linux-steed.json b/docker/aarch64-unknown-linux-steed.json
index fae3d55c7..c4bcd77b5 100644
--- a/docker/aarch64-unknown-linux-steed.json
+++ b/docker/aarch64-unknown-linux-steed.json
@@ -24,6 +24,7 @@
             "-nostartfiles"
         ]
     },
+    "target-c-int-width": "32",
     "target-endian": "little",
     "target-family": "unix",
     "target-pointer-width": "64",
diff --git a/docker/aarch64-unknown-linux-steed/Dockerfile b/docker/aarch64-unknown-linux-steed/Dockerfile
index 7dba10a05..90a1169dd 100644
--- a/docker/aarch64-unknown-linux-steed/Dockerfile
+++ b/docker/aarch64-unknown-linux-steed/Dockerfile
@@ -14,9 +14,10 @@ COPY lld.sh /
 RUN bash /lld.sh
 
 COPY qemu.sh /
-RUN bash /qemu.sh 2.9.0 aarch64
+RUN bash /qemu.sh 2.10.1 aarch64
 
 COPY aarch64-unknown-linux-steed.json /json
 
-ENV RUST_TARGET_PATH=/json \
+ENV CARGO_TARGET_AARCH64_UNKNOWN_LINUX_STEED_RUNNER=qemu-aarch64 \
+    RUST_TARGET_PATH=/json \
     RUST_TEST_THREADS=1
diff --git a/docker/arm-unknown-linux-steedeabi.json b/docker/arm-unknown-linux-steedeabi.json
index 581294513..60b670b57 100644
--- a/docker/arm-unknown-linux-steedeabi.json
+++ b/docker/arm-unknown-linux-steedeabi.json
@@ -25,6 +25,7 @@
             "-nostartfiles"
         ]
     },
+    "target-c-int-width": "32",
     "target-endian": "little",
     "target-family": "unix",
     "target-pointer-width": "32",
diff --git a/docker/arm-unknown-linux-steedeabi/Dockerfile b/docker/arm-unknown-linux-steedeabi/Dockerfile
index 9f98a1cf5..510b2cf26 100644
--- a/docker/arm-unknown-linux-steedeabi/Dockerfile
+++ b/docker/arm-unknown-linux-steedeabi/Dockerfile
@@ -14,9 +14,10 @@ COPY lld.sh /
 RUN bash /lld.sh
 
 COPY qemu.sh /
-RUN bash /qemu.sh 2.9.0 arm
+RUN bash /qemu.sh 2.10.1 arm
 
 COPY arm-unknown-linux-steedeabi.json /json
 
-ENV RUST_TARGET_PATH=/json \
+ENV CARGO_TARGET_ARM_UNKNOWN_LINUX_STEEDEABI_RUNNER=qemu-arm \
+    RUST_TARGET_PATH=/json \
     RUST_TEST_THREADS=1
diff --git a/docker/arm-unknown-linux-steedeabihf.json b/docker/arm-unknown-linux-steedeabihf.json
index 73173cd52..6c1a4d665 100644
--- a/docker/arm-unknown-linux-steedeabihf.json
+++ b/docker/arm-unknown-linux-steedeabihf.json
@@ -25,6 +25,7 @@
             "-nostartfiles"
         ]
     },
+    "target-c-int-width": "32",
     "target-endian": "little",
     "target-family": "unix",
     "target-pointer-width": "32",
diff --git a/docker/arm-unknown-linux-steedeabihf/Dockerfile b/docker/arm-unknown-linux-steedeabihf/Dockerfile
index c3ddc0baa..dbf15510e 100644
--- a/docker/arm-unknown-linux-steedeabihf/Dockerfile
+++ b/docker/arm-unknown-linux-steedeabihf/Dockerfile
@@ -14,9 +14,10 @@ COPY lld.sh /
 RUN bash /lld.sh
 
 COPY qemu.sh /
-RUN bash /qemu.sh 2.9.0 arm
+RUN bash /qemu.sh 2.10.1 arm
 
 COPY arm-unknown-linux-steedeabihf.json /json
 
-ENV RUST_TARGET_PATH=/json \
+ENV CARGO_TARGET_ARM_UNKNOWN_LINUX_STEEDEABIHF_RUNNER=qemu-arm \
+    RUST_TARGET_PATH=/json \
     RUST_TEST_THREADS=1
diff --git a/docker/armv7-unknown-linux-steedeabihf.json b/docker/armv7-unknown-linux-steedeabihf.json
index 371e582a8..963c91e06 100644
--- a/docker/armv7-unknown-linux-steedeabihf.json
+++ b/docker/armv7-unknown-linux-steedeabihf.json
@@ -25,6 +25,7 @@
             "-nostartfiles"
         ]
     },
+    "target-c-int-width": "32",
     "target-endian": "little",
     "target-family": "unix",
     "target-pointer-width": "32",
diff --git a/docker/armv7-unknown-linux-steedeabihf/Dockerfile b/docker/armv7-unknown-linux-steedeabihf/Dockerfile
index 83b41cdf5..ace0d3a29 100644
--- a/docker/armv7-unknown-linux-steedeabihf/Dockerfile
+++ b/docker/armv7-unknown-linux-steedeabihf/Dockerfile
@@ -14,9 +14,10 @@ COPY lld.sh /
 RUN bash /lld.sh
 
 COPY qemu.sh /
-RUN bash /qemu.sh 2.9.0 arm
+RUN bash /qemu.sh 2.10.1 arm
 
 COPY armv7-unknown-linux-steedeabihf.json /json
 
-ENV RUST_TARGET_PATH=/json \
+ENV CARGO_TARGET_ARMV7_UNKNOWN_LINUX_STEEDEABIHF_RUNNER=qemu-arm \
+    RUST_TARGET_PATH=/json \
     RUST_TEST_THREADS=1
diff --git a/docker/i686-unknown-linux-steed.json b/docker/i686-unknown-linux-steed.json
index a85a6c6c4..b496273bc 100644
--- a/docker/i686-unknown-linux-steed.json
+++ b/docker/i686-unknown-linux-steed.json
@@ -19,6 +19,7 @@
             "-nostartfiles"
         ]
     },
+    "target-c-int-width": "32",
     "target-endian": "little",
     "target-family": "unix",
     "target-pointer-width": "32",
diff --git a/docker/lld.sh b/docker/lld.sh
index 37e31d248..770fbbb34 100644
--- a/docker/lld.sh
+++ b/docker/lld.sh
@@ -16,14 +16,14 @@ main() {
     done
 
     cat <<EOF >>/etc/apt/sources.list
-deb http://apt.llvm.org/xenial/ llvm-toolchain-xenial-4.0 main
-deb-src http://apt.llvm.org/xenial/ llvm-toolchain-xenial-4.0 main
+deb http://apt.llvm.org/xenial/ llvm-toolchain-xenial-5.0 main
+deb-src http://apt.llvm.org/xenial/ llvm-toolchain-xenial-5.0 main
 EOF
 
     curl -L http://apt.llvm.org/llvm-snapshot.gpg.key | apt-key add -
     apt-get update
-    apt-get install --no-install-recommends -y lld-4.0
-    ln -s ld.lld-4.0 /usr/bin/ld.lld
+    apt-get install --no-install-recommends -y lld-5.0
+    ln -s ld.lld-5.0 /usr/bin/ld.lld
 
     # Clean up
     apt-get purge --auto-remove -y ${purge_list[@]}
diff --git a/docker/mips-unknown-linux-steed.json b/docker/mips-unknown-linux-steed.json
index e70febfbe..2ca095d2b 100644
--- a/docker/mips-unknown-linux-steed.json
+++ b/docker/mips-unknown-linux-steed.json
@@ -19,6 +19,7 @@
         ]
     },
     "relocation-model": "static",
+    "target-c-int-width": "32",
     "target-endian": "big",
     "target-family": "unix",
     "target-pointer-width": "32",
diff --git a/docker/mips-unknown-linux-steed/Dockerfile b/docker/mips-unknown-linux-steed/Dockerfile
index a71e05274..5b3089a4f 100644
--- a/docker/mips-unknown-linux-steed/Dockerfile
+++ b/docker/mips-unknown-linux-steed/Dockerfile
@@ -14,9 +14,10 @@ COPY lld.sh /
 RUN bash /lld.sh
 
 COPY qemu.sh /
-RUN bash /qemu.sh 2.9.0 mips
+RUN bash /qemu.sh 2.10.1 mips
 
 COPY mips-unknown-linux-steed.json /json
 
-ENV RUST_TARGET_PATH=/json \
+ENV CARGO_TARGET_MIPS_UNKNOWN_LINUX_STEED_RUNNER=qemu-mips \
+    RUST_TARGET_PATH=/json \
     RUST_TEST_THREADS=1
diff --git a/docker/mipsel-unknown-linux-steed.json b/docker/mipsel-unknown-linux-steed.json
index e495debf6..3f18675db 100644
--- a/docker/mipsel-unknown-linux-steed.json
+++ b/docker/mipsel-unknown-linux-steed.json
@@ -18,6 +18,7 @@
             "-nostartfiles"
         ]
     },
+    "target-c-int-width": "32",
     "relocation-model": "static",
     "target-endian": "little",
     "target-family": "unix",
diff --git a/docker/mipsel-unknown-linux-steed/Dockerfile b/docker/mipsel-unknown-linux-steed/Dockerfile
index 58f8682e2..ef8eb062a 100644
--- a/docker/mipsel-unknown-linux-steed/Dockerfile
+++ b/docker/mipsel-unknown-linux-steed/Dockerfile
@@ -14,9 +14,10 @@ COPY lld.sh /
 RUN bash /lld.sh
 
 COPY qemu.sh /
-RUN bash /qemu.sh 2.9.0 mipsel
+RUN bash /qemu.sh 2.10.1 mipsel
 
 COPY mipsel-unknown-linux-steed.json /json
 
-ENV RUST_TARGET_PATH=/json \
+ENV CARGO_TARGET_MIPSEL_UNKNOWN_LINUX_STEED_RUNNER=qemu-mipsel \
+    RUST_TARGET_PATH=/json \
     RUST_TEST_THREADS=1
diff --git a/docker/powerpc-unknown-linux-steed.json b/docker/powerpc-unknown-linux-steed.json
index c8ac4f95c..1d92ee876 100644
--- a/docker/powerpc-unknown-linux-steed.json
+++ b/docker/powerpc-unknown-linux-steed.json
@@ -17,6 +17,7 @@
             "-nostartfiles"
         ]
     },
+    "target-c-int-width": "32",
     "target-endian": "big",
     "target-family": "unix",
     "target-pointer-width": "32",
diff --git a/docker/powerpc-unknown-linux-steed/Dockerfile b/docker/powerpc-unknown-linux-steed/Dockerfile
index 430359458..fd921e6d3 100644
--- a/docker/powerpc-unknown-linux-steed/Dockerfile
+++ b/docker/powerpc-unknown-linux-steed/Dockerfile
@@ -13,10 +13,10 @@ RUN bash /xargo.sh
 COPY qemu.sh /
 RUN apt-get install -y --no-install-recommends \
     gcc-powerpc-linux-gnu && \
-    bash /qemu.sh 2.9.0 ppc
+    bash /qemu.sh 2.10.1 ppc
 
 COPY powerpc-unknown-linux-steed.json /json
 
-ENV CARGO_TARGET_POWERPC_UNKNOWN_LINUX_STEED_LINKER=powerpc-linux-gnu-gcc \
+ENV CARGO_TARGET_POWERPC_UNKNOWN_LINUX_STEED_RUNNER=qemu-ppc \
     RUST_TARGET_PATH=/json \
     RUST_TEST_THREADS=1
diff --git a/docker/powerpc64-unknown-linux-steed.json b/docker/powerpc64-unknown-linux-steed.json
index e0af6bdbe..5d67095fc 100644
--- a/docker/powerpc64-unknown-linux-steed.json
+++ b/docker/powerpc64-unknown-linux-steed.json
@@ -18,6 +18,7 @@
             "-nostartfiles"
         ]
     },
+    "target-c-int-width": "32",
     "target-endian": "big",
     "target-family": "unix",
     "target-pointer-width": "64",
diff --git a/docker/powerpc64-unknown-linux-steed/Dockerfile b/docker/powerpc64-unknown-linux-steed/Dockerfile
index 86ae9fc15..53aa919b5 100644
--- a/docker/powerpc64-unknown-linux-steed/Dockerfile
+++ b/docker/powerpc64-unknown-linux-steed/Dockerfile
@@ -13,10 +13,11 @@ RUN bash /xargo.sh
 COPY qemu.sh /
 RUN apt-get install -y --no-install-recommends \
     gcc-powerpc64-linux-gnu && \
-    bash /qemu.sh 2.9.0 ppc64
+    bash /qemu.sh 2.10.1 ppc64
 
 COPY powerpc64-unknown-linux-steed.json /json
 
 ENV CARGO_TARGET_POWERPC64_UNKNOWN_LINUX_STEED_LINKER=powerpc64-linux-gnu-gcc \
+    CARGO_TARGET_POWERPC64_UNKNOWN_LINUX_STEED_RUNNER=qemu-ppc64 \
     RUST_TARGET_PATH=/json \
     RUST_TEST_THREADS=1
diff --git a/docker/powerpc64le-unknown-linux-steed.json b/docker/powerpc64le-unknown-linux-steed.json
index 2ce3308d8..45267d337 100644
--- a/docker/powerpc64le-unknown-linux-steed.json
+++ b/docker/powerpc64le-unknown-linux-steed.json
@@ -18,6 +18,7 @@
             "-nostartfiles"
         ]
     },
+    "target-c-int-width": "32",
     "target-endian": "little",
     "target-family": "unix",
     "target-pointer-width": "64",
diff --git a/docker/powerpc64le-unknown-linux-steed/Dockerfile b/docker/powerpc64le-unknown-linux-steed/Dockerfile
index cec07ee5e..b313a58de 100644
--- a/docker/powerpc64le-unknown-linux-steed/Dockerfile
+++ b/docker/powerpc64le-unknown-linux-steed/Dockerfile
@@ -13,10 +13,10 @@ RUN bash /xargo.sh
 COPY qemu.sh /
 RUN apt-get install -y --no-install-recommends \
     gcc-powerpc64le-linux-gnu && \
-    bash /qemu.sh 2.9.0 ppc64le
+    bash /qemu.sh 2.10.1 ppc64le
 
 COPY powerpc64le-unknown-linux-steed.json /json
 
-ENV CARGO_TARGET_POWERPC64LE_UNKNOWN_LINUX_STEED_LINKER=powerpc64le-linux-gnu-gcc \
+ENV CARGO_TARGET_POWERPC64LE_UNKNOWN_LINUX_STEED_RUNNER=qemu-ppc64le \
     RUST_TARGET_PATH=/json \
     RUST_TEST_THREADS=1
diff --git a/docker/x86_64-unknown-linux-steed.json b/docker/x86_64-unknown-linux-steed.json
index 4d2ae0d2a..5f60ed30f 100644
--- a/docker/x86_64-unknown-linux-steed.json
+++ b/docker/x86_64-unknown-linux-steed.json
@@ -19,6 +19,7 @@
             "-nostartfiles"
         ]
     },
+    "target-c-int-width": "32",
     "target-endian": "little",
     "target-family": "unix",
     "target-pointer-width": "64",
diff --git a/src/lib.rs b/src/lib.rs
index b52949944..5d570f1a1 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -7,6 +7,9 @@
 #![feature(cfg_target_vendor)]
 #![feature(collections_range)]
 #![feature(compiler_builtins_lib)]
+#![feature(const_atomic_bool_new)]
+#![feature(const_atomic_u8_new)]
+#![feature(const_atomic_usize_new)]
 #![feature(const_fn)]
 #![feature(core_intrinsics)]
 #![feature(custom_attribute)]
@@ -22,8 +25,8 @@
 #![feature(lang_items)]
 #![feature(macro_reexport)]
 #![feature(naked_functions)]
-#![feature(optin_builtin_traits)]
 #![feature(needs_drop)]
+#![feature(optin_builtin_traits)]
 #![feature(placement_new_protocol)]
 #![feature(prelude_import)]
 #![feature(rand)]