Updated Docker setup to use GCC 4.8

Now that we depend on C++11, we need at least GCC 4.8 instead of 4.7.
This change updates the Docker setup to continue using CentOS 6.6 but
with GCC 4.8.

I also added libm to the whitelist for dynamically linked libraries for
the ARM64 protoc binary.

protoc-artifacts/Dockerfile

@@ -28,15 +28,14 @@ RUN wget -q http://apache.cs.utah.edu/maven/maven-3/3.3.9/binaries/apache-maven-
     tar xz -C /var/local
 ENV PATH /var/local/apache-maven-3.3.9/bin:$PATH
 
-# Install GCC 4.7 to support -static-libstdc++
-RUN wget http://people.centos.org/tru/devtools-1.1/devtools-1.1.repo -P /etc/yum.repos.d && \
-    bash -c 'echo "enabled=1" >> /etc/yum.repos.d/devtools-1.1.repo' && \
-    bash -c "sed -e 's/\$basearch/i386/g' /etc/yum.repos.d/devtools-1.1.repo > /etc/yum.repos.d/devtools-i386-1.1.repo" && \
-    sed -e 's/testing-/testing-i386-/g' -i /etc/yum.repos.d/devtools-i386-1.1.repo && \
+# Install GCC 4.8 to support -static-libstdc++
+RUN wget http://people.centos.org/tru/devtools-2/devtools-2.repo -P /etc/yum.repos.d && \
+    bash -c 'echo "enabled=1" >> /etc/yum.repos.d/devtools-2.repo' && \
+    bash -c "sed -e 's/\$basearch/i386/g' /etc/yum.repos.d/devtools-2.repo > /etc/yum.repos.d/devtools-i386-2.repo" && \
+    sed -e 's/testing-/testing-i386-/g' -i /etc/yum.repos.d/devtools-i386-2.repo && \
     rpm --rebuilddb && \
-    yum install -y devtoolset-1.1 \
-                   devtoolset-1.1-libstdc++-devel \
-                   devtoolset-1.1-libstdc++-devel.i686 && \
+    yum install -y devtoolset-2-gcc devtoolset-2-gcc-c++ devtoolset-2-binutils devtoolset-2-libstdc++-devel \
+                   devtoolset-2-gcc.i686 devtoolset-2-gcc-c++.i686 devtoolset-2-binutils.i686 devtoolset-2-libstdc++-devel.i686 && \
     yum clean all
 
 COPY scl-enable-devtoolset.sh /var/local/

protoc-artifacts/build-protoc.sh

@@ -150,7 +150,7 @@ checkDependencies ()
       white_list="linux-vdso64\.so\.1\|libpthread\.so\.0\|libm\.so\.6\|libc\.so\.6\|libz\.so\.1\|ld64\.so\.2"
     elif [[ "$ARCH" == aarch_64 ]]; then
       dump_cmd='objdump -p '"$1"' | grep NEEDED'
-      white_list="libpthread\.so\.0\|libc\.so\.6\|ld-linux-aarch64\.so\.1"
+      white_list="libpthread\.so\.0\|libm\.so\.6\|libc\.so\.6\|ld-linux-aarch64\.so\.1"
     fi
   elif [[ "$OS" == osx ]]; then
     dump_cmd='otool -L '"$1"' | fgrep dylib'

protoc-artifacts/scl-enable-devtoolset.sh

@@ -10,4 +10,4 @@ quote() {
   done
 }
 
-exec scl enable devtoolset-1.1 "$(quote "$@")"
+exec scl enable devtoolset-2 "$(quote "$@")"