- license update: BSD-3-Clause and GPL-2.0+ and MIT
SPDX

- update to version 3.37
* New and rewritten pages
getent.1
New page to document 'getent' binary provided by glibc
* Changes to individual pages
bdflush.2
Note that bdflush() is deprecated, and does nothing
nfsservctl.2
Note that this system call was removed in Linux 3.1
ptrace.2
add extended description of various ptrace quirks
Changes include:
s/parent/tracer/g, s/child/tracee/g - ptrace interface now
is sufficiently cleaned up to not treat tracing process
as parent.
Deleted several outright false statements:
- pid 1 can be traced
- tracer is not shown as parent in ps output
- PTRACE_ATTACH is not "the same behavior as if tracee had done
a PTRACE_TRACEME": PTRACE_ATTACH delivers a SIGSTOP.
- SIGSTOP _can_ be injected.
- Removed mentions of SunOS and Solaris as irrelevant.
- Added a few more known bugs.
Added a large block of text in DESCRIPTION which doesn't focus
on mechanical description of each flag and operation, but rather
tries to describe a bigger picture. The targeted audience is
a person which is reasonably knowledgeable in Unix but did not