Whenever attempting to use any ncurses functionality within cscope, a
page fault would result within the ncurses library.

    Program received signal SIGSEGV, Segmentation fault.
    0x00007ffff7fad3cf in termattrs_sp () from .../lib/libncursesw.so.6
    (gdb) bt
    #0  0x00007ffff7fad3cf in termattrs_sp () from .../lib/libncursesw.so.6
    #1  0x00007ffff7faa794 in _nc_setupscreen_sp () from .../lib/libncursesw.so.6
    #2  0x00007ffff7fa614c in newterm_sp () from .../lib/libncursesw.so.6
    #3  0x00007ffff7fa65b9 in newterm () from .../lib/libncursesw.so.6
    #4  0x00007ffff7fa2970 in initscr () from .../lib/libncursesw.so.6
    #5  0x0000000000403dc2 in main (argc=<optimized out>, argv=0x7fffffffcea8) at main.c:574

This is due to a conflict between libtinfo.so and libtinfow.so. Both are
linked into cscope:

    $ ldd $(which cscope)
    /bin/bash: .../lib/libtinfo.so.6: no version information available (required by /bin/bash)
        linux-vdso.so.1 (0x00007fff5dbcb000)
        libncursesw.so.6 => .../lib/libncursesw.so.6 (0x00007f435cc69000)
        libtinfo.so.6 => .../lib/libtinfo.so.6 (0x00007f435cc2c000)
        libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f435ca29000)
        libtinfow.so.6 => .../lib/libtinfow.so.6 (0x00007f435c9e8000)
        /lib64/ld-linux-x86-64.so.2 (0x00007f435cca7000)

Specifically linking libtinfow.so instead of libtinfo.so resolves the
issue.

All instances of '...' above represent the path to the installed ncurses
for Spack.

Git 2.24 introduced a feature flag for repositories with many files, see:
https://github.blog/2019-11-03-highlights-from-git-2-24/#feature-macros

Since Spack's Git repository contains roughly 8,500 files, it can be
worthwhile to enable this, especially on slow file systems such as NFS:
```
$ hyperfine --warmup 3 'cd spack-default; git status' 'cd spack-manyfiles; git status'
Benchmark #1: cd spack-default; git status
  Time (mean ± σ):      3.388 s ±  0.095 s    [User: 256.2 ms, System: 625.8 ms]
  Range (min … max):    3.168 s …  3.535 s    10 runs

Benchmark #2: cd spack-manyfiles; git status
  Time (mean ± σ):     168.7 ms ±  10.9 ms    [User: 98.6 ms, System: 126.1 ms]
  Range (min … max):   144.8 ms … 188.0 ms    19 runs

Summary
  'cd spack-manyfiles; git status' ran
   20.09 ± 1.42 times faster than 'cd spack-default; git status'
```