You can create a shell script that does more or less the following:
#! /usr/bin/env sh
# Remove the script's path from the PATH variable to avoid recursive calls
SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
export PATH=${PATH/$SCRIPT_DIR:/}
# Set the environment up
source /opt/intel/bin/compilervars.sh intel64
# Call make with the given arguments
make "$@"
Save it into a file named "make" in an empty directory somewhere, make it executable, then change the build environment in QT Creator to prepend PATH with the script's directory:
PATH=[dir-of-make-script]:${Env:PATH}
You can do this either in the project settings or once and for all in the kit settings.
Like this, QT Creator will be fooled into calling your make script which sets up your environment before calling the actual make binary. I use a similar technique under Windows with Linux cross-toolchains and it has been working well so far.