Merge changes from the Perl side

This contains many changes from https://80x24.org/mwrap-perl.git
commit

* Built-in RCU-friendly version of dlmalloc, no more fragile dlsym(3m)
  resolution of malloc-family functions in the constructor

* Allocations are now backed by O_TMPFILE on $TMPDIR on modern Linux.
  Since mwrap increases memory usage greatly and I needed to use it
  on a system where I needed more VM space but lacked the ability
  to add swap.

* Configurable C backtrace level via MWRAP=bt:$DEPTH where $DEPTH
  is a non-negative integer.  Be careful about increasing it, even
  a depth of 3-4 can be orders-of-magnitude more expensive in
  time and space.  This can be changed dynamically at runtime via
  local HTTP (see below).

* Embedded per-process local-socket-only HTTP server obsoletes
  MwrapRack when combined with mwrap-rproxy from the Perl dist
  (set `MWRAP=socket_dir:/dir/of/sockets')
  See https://80x24.org/mwrap-perl/20221210015518.272576-4-e@80x24.org/
  for more info.

  It now supports downloading CSV (suitable for importing into sqlite 3.32.0+)

* License switched to GPL-3+ to be compatible with GNU binutils
  since we may take code from addr2line in the future.

* libxxhash supported if XXH3_64bits is available.

1 files changed, 36 insertions, 0 deletions

diff --git a/VERSION-GEN b/VERSION-GEN
new file mode 100755
index 0000000..ae66e94
--- /dev/null
+++ b/VERSION-GEN
@@ -0,0 +1,36 @@
+#!/bin/sh
+VF=lib/mwrap/version.rb
+DEF_VER=v2.3.0
+VN=$(git describe HEAD 2>/dev/null)
+if test $? -eq 0
+then
+        case "$VN" in
+        v[0-9]*)
+                set -e
+                git update-index -q --refresh
+                set +e
+                git diff-index --quiet HEAD -- || VN="$VN-dirty"
+                set -e
+                VN=$(echo $VN | tr '-' '.')
+                ;;
+        esac
+fi
+set -e
+
+case $VN in
+'') VN="$DEF_VER" ;;
+esac
+
+VN=$(expr "$VN" : v*'\(.*\)')
+VC=unset
+if test -r $VF
+then
+        VC="$(cat $VF)"
+fi
+
+new="module Mwrap; VERSION = '$VN'.freeze; end"
+if test x"$new" != x"$VC"
+then
+        echo "$new" >$VF
+fi
+echo $VN