This allows us to get the terminfo information without linking against curses.
That means we can get by without a bunch of awkward C-API trickery.
There is no global "cur_term" kept by a library for us that we need to invalidate.
Note that it still requires a "unhashed terminfo database", and I don't know how well it handles termcap.
I am not actually sure if there are systems that *can't* have terminfo, everything I looked at
has the ncurses terminfo available to install at least.
We use this so you can run fish from the build directory and it picks
up its data files.
If this wasn't canonicalized, that would break if you're building with
a $PWD through a symlink.
NCurses headers contain this conditional "#define cur_term":
print "#elif @cf_cv_enable_reentrant@"
print "NCURSES_WRAPPED_VAR(TERMINAL *, cur_term);"
print "#define cur_term NCURSES_PUBLIC_VAR(cur_term())"
print "#else"
OpenSUSE Tumbleweed uses this configuration option; For reentrancy, cur_term
is a function. If the NCurses autoconf variable @NCURSES_WRAP_PREFIX@
is not changed from its default, the function is called _nc_cur_term.
I'm not sure if we have a need to support non-default @NCURSES_WRAP_PREFIX@
but if we do there are various ways;
- search for the symbol with the cur_term suffix
- figure out the prefix based on the local curses installation,
for example by looking at the header files.
Fixes#10243
Since none of the compiles(xxx) calls are to particularly complex code, we can
just use `rsconf` directly to test for the presence of the symbols or headers as
needed.
Note that it seems at least some of the previous detection was not working
correctly; in particular HAVE_PIPE2 was evaluating to false on my WSL install
where pipe2(2) was available (caught because it revealed some compilation errors
in that conditional compilation path after porting).
I kept the cfg names and the tests themselves mostly as-is, though we might want
to change that to conform with the rust convention of lowercase cfg names and
decide whether we want to prefix all these with have_, fish_, or nothing at all.
Also the posix_spawn() test should probably check for the symbol `posix_spawn()`
rather than the header `spawn.h` since we don't use it via the header but rather
via the symbol (but in reality they're almost certainly going to give the same
result).
