fix valgrind

ci/travis/valgrind.sh

@@ -16,9 +16,6 @@ if [[ -z "$CXXSTD" ]]; then
     CXXSTD=03
 fi
 
-# required for valgrind to work:
-apt-get install libc6-dbg
-
 # valgrind on travis is 3.10 which is old
 # using valgrind 3.14 but we have to build it
 

templates/.travis.yml

@@ -78,6 +78,7 @@ anchors:
                                            "libstdc++-7-dev" ], sources: [ "llvm-toolchain-trusty-5.0",
                                                                            "ubuntu-toolchain-r-test"   ] } }
   clang-6:  &clang-6  { apt: { packages: [ "clang-6.0",
+                                           "libc6-dbg",
                                            "libc++-dev",
                                            "libstdc++-8-dev" ], sources: [ "llvm-toolchain-trusty-6.0",
                                                                            "ubuntu-toolchain-r-test"   ] } }