Fix potential buffer overflow if `length` (now `length_of_initial_text`)
is less than the `strlen` computed length of text.
Rename variables to clarify usage.
Eliminate the unnecessary use of `strlen`.
Support for ORTHO_VIEWS has been broken since commit
db514a5ded in December 2004.
`git blame HEAD -L872,+4 -- similar/editor/meddraw.cpp`:
```
db514a5ded main/editor/meddraw.c (Bradley Bell 2004-12-19 13:54:27 +0000 872) }
db514a5ded main/editor/meddraw.c (Bradley Bell 2004-12-19 13:54:27 +0000 873) } else
db514a5ded main/editor/meddraw.c (Bradley Bell 2004-12-19 13:54:27 +0000 874) #if ORTHO_VIEWS
db514a5ded main/editor/meddraw.c (Bradley Bell 2004-12-19 13:54:27 +0000 875) else if ( screen_canvas == TopViewBox->canvas )
```
When ORTHO_VIEWS is true, this code expands to `} else else if (...)`; a
double-else is not legal, so the code cannot have been compiled with
ORTHO_VIEWS enabled. All 4 of the relevant lines date to db514a5ded,
which itself is an import of files from the D1X editor.
When joystick support is not present, `event_joystick_get_button` is not
declared in joy.h.
Fixes: c24864b180 ("make menus controllable with joystick")
This is necessarily incomplete since it can only check ranges that have
a compile-time static size. However, it catches some simple mistakes,
and imposes no runtime cost, so it is still useful.
Define separate enum values for rotation data in both the high bits,
where it is usually kept, and the low bits, where it is sometimes used
for math or comparisons.
Define an enum value to represent the composite of the index and the
rotation, since the composite is not suitable for use as an array
subscript. Add helper functions to extract the component pieces.
