WIP: Add Saleae logic analyzer software

TODO: Fix segfault on startup.
saleae-logic: a bit less patching seems to fix the segfault

Now the issue is that Logic wants to write to the directory it is
installed to (which doesn't work because it is read-only):

$ strace ./result/Logic
[...]
open("/nix/store/zyr9w95lzz44an4rm4nzphrkcwy1ydqa-saleae-logic-1.1.15/Settings/settings.xml", O_RDONLY) = -1 ENOENT (No such file or directory)
futex(0x7f5961e9cbc4, FUTEX_WAKE_PRIVATE, 2147483647) = 0
open("/nix/store/zyr9w95lzz44an4rm4nzphrkcwy1ydqa-saleae-logic-1.1.15/Settings/settings.xml", O_WRONLY|O_CREAT|O_TRUNC, 0666) = -1 EROFS (Read-only file system)
write(2, "terminate called after throwing "..., 48terminate called after throwing an instance of ') = 48
write(2, "boost::archive::archive_exceptio"..., 33boost::archive::archive_exception) = 33
write(2, "'\n", 2')                      = 2
write(2, "  what():  ", 11  what():  )             = 11
write(2, "stream error", 12stream error)            = 12
write(2, "\n", 1)                       = 1
rt_sigprocmask(SIG_UNBLOCK, [ABRT], NULL, 8) = 0
tgkill(28156, 28156, SIGABRT)           = 0
--- SIGABRT {si_signo=SIGABRT, si_code=SI_TKILL, si_pid=28156, si_uid=1000} ---
+++ killed by SIGABRT (core dumped) +++
Aborted
saleae-logic: code style
saleae-logic: doesn't segfault anymore

But it dies when it tries to write to its installation path (because
that is read-only). The next Logic release should have command line
flags that can tell it where to write stuff.