upgrade to alpine 3.7

.gitlab-ci.yml

@@ -5,18 +5,18 @@
 # files implicitly passed between jobs or stages, only artifacts and maybe
 # cache (depends on configuration).
-image: alpine:3.6
+image: alpine:3.7
 before_script:
   - case "$CI_BUILD_NAME" in
-      *-clang) export CXX=clang++ EXTRA_PKGS="$EXTRA_PKGS clang llvm4-dev";;
+      *-clang) export CXX=clang++ EXTRA_PKGS="$EXTRA_PKGS clang llvm5-dev";;
       *) export CXX=g++;;
     esac
   - export JOBS=$(grep -c processor /proc/cpuinfo)
   - apk add --no-cache build-base bash libexecinfo-dev
         cppunit-dev libxml2-dev tclap-dev readline-dev $EXTRA_PKGS
   - case "$CI_BUILD_NAME" in
-      *-clang) ln -s /usr/lib/llvm4/lib/LLVMgold.so /usr/lib/LLVMgold.so;;
+      *-clang) ln -s /usr/lib/llvm5/lib/LLVMgold.so /usr/lib/LLVMgold.so;;
       *) ;;
     esac
   - echo USE_RAMDISK=0 >> build.conf