[lldb][Docs] Add Curses version note to build page

This explains a thing that hit me on FreeBSD because the base system
has an ncursesw at one version and I installed from pkg another
version that was simply ncurses (no wide char support).

For whatever reason, when we pass -lcurses to the linker it ends up
picking bits of both installs. This led to lldb crashing immediately
if you tried to use the `gui` command.

In a way that gave little information but I stumbled onto
https://github.com/vifm/vifm/issues/325 which is very similar.

```
ec2-user@freebsd:~/build-llvm $ ldd ./bin/lldb | grep curses
	libncursesw.so.9 => /lib/libncursesw.so.9 (0x6a515206e000)
	libncurses.so.6 => /usr/local/lib/libncurses.so.6 (0x6a5158e86000)
```

We should only see one version, and it and libpanel etc should
all have "w" or not have "w". This was not the case for my build.

What I can see from the CMake side seemed fine, it found the pkg
installed ncurses in /usr/local. Something else must decide that
-lcurses should pull in the other one.

Regardless, I don't know how to fix that but the solution for most
people is just not to add another ncurses if they already have one.
So I've added a note saying so, and how to check what your lldb
is using.
1 file changed
tree: 6d3eadd60313a1dd40b708b8559ef0dcbad8e180
  1. .ci/
  2. .github/
  3. bolt/
  4. clang/
  5. clang-tools-extra/
  6. cmake/
  7. compiler-rt/
  8. cross-project-tests/
  9. flang/
  10. libc/
  11. libclc/
  12. libcxx/
  13. libcxxabi/
  14. libunwind/
  15. lld/
  16. lldb/
  17. llvm/
  18. llvm-libgcc/
  19. mlir/
  20. openmp/
  21. polly/
  22. pstl/
  23. runtimes/
  24. third-party/
  25. utils/
  26. .clang-format
  27. .clang-tidy
  28. .git-blame-ignore-revs
  29. .gitattributes
  30. .gitignore
  31. .mailmap
  32. CODE_OF_CONDUCT.md
  33. CONTRIBUTING.md
  34. LICENSE.TXT
  35. pyproject.toml
  36. README.md
  37. SECURITY.md
README.md

The LLVM Compiler Infrastructure

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