Problem: Execution stack is incomplete and inefficient.
Solution: Introduce a proper execution stack and use it instead of
sourcing_name/sourcing_lnum. Create a string only when used.
1a47ae32cd
Omit test_debugger.vim: superseded by later patches.
Omit check_map_keycodes(): N/A.
Omit kword_test.c: N/A (converted to a unit test).
Problem: Support for user commands is spread out. No good reason to make
user commands optional.
Solution: Move user command support to usercmd.c. Always enable the
user_commands feature.
ac9fb18020
