patchRcPathPosix(){
    local FILE_TO_PATCH="$1"
    local SOURCETIME_PATH="$2"
    local FILE_TO_WORK_ON="$(mktemp "$(basename "$FILE_TO_PATCH").XXXXXX.tmp")"
    cat <<EOF >> "$FILE_TO_WORK_ON"
# Lines to add to PATH the source-time utilities for Nixpkgs packaging
if [ -n "\${NIXPKGS_SOURCETIME_PATH-}" ]; then
    NIXPKGS_SOURCETIME_PATH_OLD="\$NIXPKGS_SOURCETIME_PATH;\${NIXPKGS_SOURCETIME_PATH_OLD-}"
fi
NIXPKGS_SOURCETIME_PATH="$SOURCETIME_PATH"
if [ -n "\$PATH" ]; then
    PATH="\$NIXPKGS_SOURCETIME_PATH:\$PATH";
else
    PATH="\$NIXPKGS_SOURCETIME_PATH"
fi
export PATH
# End of lines to add to PATH source-time utilities for Nixpkgs packaging
EOF
    cat "$FILE_TO_PATCH" >> "$FILE_TO_WORK_ON"
    cat <<EOF >> "$FILE_TO_WORK_ON"
# Lines to clean up inside PATH the source-time utilities for Nixpkgs packaging
if [ -n "\${PATH-}" ]; then
    PATH="\$(echo "\$PATH" | @sed@ "s#\$NIXPKGS_SOURCETIME_PATH##" | @sed@ "s#::#:#g" | @sed@ "s#^:##" | @sed@ "s#:\\\$##")"
    export PATH
fi
if [ -n "\${NIXPKGS_SOURCETIME_PATH_OLD-}" ]; then
    NIXPKGS_SOURCETIME_PATH="\$(echo "\$NIXPKGS_SOURCETIME_PATH_OLD" | @sed@ "s#\\([^;]\\);.*#\\1#")"
    NIXPKGS_SOURCETIME_PATH_OLD="\$(echo "\$NIXPKGS_SOURCETIME_PATH_OLD" | @sed@ "s#[^;];\\(.*\\)#\\1#")"
else
    unset NIXPKGS_SOURCETIME_PATH
fi
if [ -z "\${NIXPKGS_SOURCETIME_PATH_OLD-}" ]; then
    unset NIXPKGS_SOURCETIME_PATH_OLD
fi
# End of lines to clean up inside PATH the source-time utilities for Nixpkgs packaging
EOF
    cat "$FILE_TO_WORK_ON" > "$FILE_TO_PATCH"
    rm "$FILE_TO_WORK_ON"
}