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, 35 insertions, 0 deletions

diff --git a/mwrap.gemspec b/mwrap.gemspec
new file mode 100644
index 0000000..dc99924
--- /dev/null
+++ b/mwrap.gemspec
@@ -0,0 +1,35 @@
+git_manifest = `git ls-files 2>/dev/null`.split("\n")
+git_ok = $?.success?
+git_manifest << 'lib/mwrap/version.rb'.freeze # generated by ./VERSION-GEN
+manifest = File.exist?('MANIFEST') ?
+  File.readlines('MANIFEST').map!(&:chomp).delete_if(&:empty?) : git_manifest
+if git_ok && manifest != git_manifest
+  tmp = "MANIFEST.#$$.tmp"
+  File.open(tmp, 'w') { |fp| fp.puts(git_manifest.join("\n")) }
+  File.rename(tmp, 'MANIFEST')
+  system('git add MANIFEST')
+end
+
+version = `./VERSION-GEN`.chomp
+$?.success? or abort './VERSION-GEN failed'
+
+Gem::Specification.new do |s|
+  s.name = 'mwrap'
+  s.version = version
+  s.homepage = 'https://80x24.org/mwrap/'
+  s.authors = ["mwrap hackers"]
+  s.summary = 'LD_PRELOAD malloc wrapper for Ruby'
+  s.executables = %w(mwrap)
+  s.files = manifest
+  s.description = <<~EOF
+mwrap wraps all malloc, calloc, and realloc calls to trace the Ruby
+source location of such calls and bytes allocated at each callsite.
+  EOF
+  s.email = %q{e@80x24.org}
+  s.test_files = Dir['test/test_*.rb']
+  s.extensions = %w(ext/mwrap/extconf.rb)
+
+  s.add_development_dependency('test-unit', '~> 3.0')
+  s.add_development_dependency('rake-compiler', '~> 1.0')
+  s.licenses = %w(GPL-3.0+)
+end