Merge branch 'lintao/build/hint-to-users' into 'master'

Improve the build script.

See merge request cepc/CEPCSW!114

cmake/CEPCSWEnv.cmake

 # This variable will be used by GaudiToolbox.cmake to generate the cepcswenv.sh
 
 set(RUN_SCRIPT_EXTRA_COMMANDS "${RUN_SCRIPT_EXTRA_COMMANDS}
-export CEPCSW_ROOT=${CMAKE_SOURCE_DIR}
 
-export DETCEPCV4ROOT=${CMAKE_SOURCE_DIR}/Detector/DetCEPCv4
-export DETCRDROOT=${CMAKE_SOURCE_DIR}/Detector/DetCRD
-export DETDRIFTCHAMBERROOT=${CMAKE_SOURCE_DIR}/Detector/DetDriftChamber
+CEPCSW_PROJECT_SOURCE_DIR=${CMAKE_SOURCE_DIR} # this is hardcode
+export CEPCSW_ROOT=\${CEPCSW_ROOT:-\${CEPCSW_PROJECT_SOURCE_DIR}} # allow user to override the default
+
+export DETCEPCV4ROOT=\${CEPCSW_ROOT}/Detector/DetCEPCv4
+export DETCRDROOT=\${CEPCSW_ROOT}/Detector/DetCRD
+export DETDRIFTCHAMBERROOT=\${CEPCSW_ROOT}/Detector/DetDriftChamber
 ")

setup.sh

@@ -46,6 +46,7 @@ function setup-external() {
 function setup-install-area() {
     local installarea=$THISSCRITDIR/InstallArea
     if [ ! -d "$installarea" ]; then
+        info: "The InstallArea is not created yet. Please run ./build.sh first, then source setup.sh again."
         return
     fi