Package libcurses

Nobody has claimed this yet.

This will allow include-what-you-use packages to be portable across more linux versions

TODO: lldb may also gain added functionality by using this curses package on linux

Currently:

```
$ ldd mason_packages/linux-x86_64/llvm/3.9.1/bin/include-what-you-use
linux-vdso.so.1 => (0x00007ffd3a9db000)
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fd5db5a4000)
libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007fd5db38d000)
libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007fd5db16f000)
libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x00007fd5daf58000)
libncurses.so.5 => /lib/x86_64-linux-gnu/libncurses.so.5 (0x00007fd5dad37000)
libtinfo.so.5 => /lib/x86_64-linux-gnu/libtinfo.so.5 (0x00007fd5dab0f000)
libform.so.5 => /usr/lib/x86_64-linux-gnu/libform.so.5 (0x00007fd5da900000)
libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007fd5da6fc000)
librt.so.1 => /lib/x86_64-linux-gnu/librt.so.1 (0x00007fd5da4f3000)
libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007fd5da1f7000)
/lib64/ld-linux-x86-64.so.2 (0x00007fd5db969000)
```

Locate the mason package definition for libcurses and the include-what-you-use package that currently links libncurses.so.5, libtinfo.so.5, and libform.so.5. Compare the resulting dependency set across Linux versions; done means libcurses is packaged and include-what-you-use can use it portably, with any lldb benefit assessed separately.

Written by the indexing model from the issue text.