craftenv.sh: Don't export environment variables starting with BASH_FUNC_
Summary:
Otherwise I get the following warning:
bash: export: BASH_FUNC_generate_command_executed_sequence%%=()': not a valid identifier`
It turns out I have the following variable in my environment:
BASH_FUNC_generate_command_executed_sequence%%=() { printf '\e\7' }
Test Plan: I no longer get the warning when sourcing craftenv.sh
Reviewers: vonreth
Reviewed By: vonreth
Differential Revision: https://phabricator.kde.org/D11424