install binutils manually

.travis.yml

@@ -6,22 +6,15 @@ matrix:
     - env: TARGET=thumbv6m-none-eabi
       os: linux
       dist: trusty
-      addons:
+      sudo: required
-        apt:
-          packages: &cortex
-            - gcc-arm-none-eabi
     - env: TARGET=thumbv7m-none-eabi
       os: linux
       dist: trusty
-      addons:
+      sudo: required
-        apt:
-          packages: *cortex
     - env: TARGET=thumbv7em-none-eabi
       os: linux
       dist: trusty
-      addons:
+      sudo: required
-        apt:
-          packages: *cortex
     - env: TARGET=i586-unknown-linux-gnu
       os: linux
       services: docker

ci/install.sh

@@ -33,6 +33,13 @@ install_binutils() {
             brew install binutils
             ;;
     esac
+
+    case $TARGET in
+        thumbv*-none-eabi)
+            sudo apt-get install -y --no-install-recommends \
+                 binutils-arm-none-eabi
+            ;;
+    esac
 }
 
 install_c_toolchain() {