scripts: set PACKER_RACE to build with race detector

scripts/build.sh

@@ -20,9 +20,16 @@ cd $DIR
 GIT_COMMIT=$(git rev-parse HEAD)
 GIT_DIRTY=$(test -n "`git status --porcelain`" && echo "+CHANGES" || true)
 
+# If we're building a race-enabled build, then set that up.
+if [ ! -z $PACKER_RACE ]; then
+    echo -e "${OK_COLOR}--> Building with race detection enabled${NO_COLOR}"
+    PACKER_RACE="-race"
+fi
+
 # Compile the main Packer app
 echo -e "${OK_COLOR}--> Compiling Packer${NO_COLOR}"
 go build \
+    ${PACKER_RACE} \
     -ldflags "-X github.com/mitchellh/packer/packer.GitCommit ${GIT_COMMIT}${GIT_DIRTY}" \
     -v \
     -o bin/packer .
@@ -32,6 +39,7 @@ for PLUGIN in $(find ./plugin -mindepth 1 -maxdepth 1 -type d); do
     PLUGIN_NAME=$(basename ${PLUGIN})
     echo -e "${OK_COLOR}--> Compiling Plugin: ${PLUGIN_NAME}${NO_COLOR}"
     go build \
+        ${PACKER_RACE} \
         -ldflags "-X github.com/mitchellh/packer/packer.GitCommit ${GIT_COMMIT}${GIT_DIRTY}" \
         -v \
         -o bin/packer-${PLUGIN_NAME} ${PLUGIN}