chore(tools): improve build_static_qt, add a note to export Qt5_DIR and PATH

tools/build_static_qt

@@ -10,6 +10,7 @@ QT_VERSION='5.10'
 # ==============================================================================
 
 RED='\e[1;31m'
+BLUE='\e[1;34m'
 NC='\e[0m'
 
 SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
@@ -71,3 +72,7 @@ if [[ $? != 0 ]] ; then
 fi
 
 make -r -j5
+
+printf "${NC}Please export configuration variables like this:${NC}\n"
+printf "${BLUE}export PATH=\"/opt/qt${QT_VERSION}/bin/:\$PATH\"${NC}\n"
+printf "${BLUE}export Qt5_DIR=\"/opt/qt${QT_VERSION}/lib/cmake/\"${NC}\n"