meson: add initial support

meson.build

+project('opendht', 'c', 'cpp',
+    version: '2.5.0',
+    default_options: [
+        'cpp_std=c++17',
+        'warning_level=3'
+    ])
+
+gnutls = dependency('gnutls')
+nettle = dependency('nettle')
+msgpack = dependency('msgpack-cxx')
+argon2 = dependency('libargon2')
+openssl = dependency('openssl', required: get_option('proxy_client'))
+jsoncpp = dependency('jsoncpp', required: get_option('proxy_client'))
+
+dirs=[]
+if host_machine.system() == 'freebsd'
+    dirs+='/usr/local/lib'
+elif host_machine.system() == 'darwin'
+    dirs+='/opt/homebrew/lib'
+endif
+http_parser = meson.get_compiler('c').find_library('http_parser', dirs: dirs, required: get_option('proxy_client'))
+deps = [gnutls, nettle, msgpack, argon2, openssl, jsoncpp, http_parser]
+
+add_project_arguments('-DMSGPACK_NO_BOOST', language : 'cpp')
+add_project_arguments(['-Wno-return-type','-Wno-deprecated','-Wnon-virtual-dtor','-pedantic-errors','-fvisibility=hidden'], language : 'cpp')
+
+opendht_inc = include_directories('include/opendht')
+opendht_src = [
+    'src/utils.cpp',
+    'src/infohash.cpp',
+    'src/crypto.cpp',
+    'src/default_types.cpp',
+    'src/node.cpp',
+    'src/value.cpp',
+    'src/dht.cpp',
+    'src/callbacks.cpp',
+    'src/routing_table.cpp',
+    'src/node_cache.cpp',
+    'src/network_engine.cpp',
+    'src/securedht.cpp',
+    'src/dhtrunner.cpp',
+    'src/log.cpp',
+    'src/op_cache.cpp',
+    'src/network_utils.cpp'
+]
+if jsoncpp.found()
+    opendht_src += ['src/base64.cpp']
+    add_project_arguments('-DOPENDHT_JSONCPP', language : 'cpp')
+endif
+if http_parser.found()
+    opendht_src += ['src/http.cpp', 'src/compat/os_cert.cpp']
+    if host_machine.system() == 'darwin'
+        deps+=dependency('appleframeworks', modules : ['CoreFoundation', 'Security'])
+    endif
+endif
+if get_option('proxy_client').enabled()
+    opendht_src += ['src/dht_proxy_client.cpp']
+    add_project_arguments('-DOPENDHT_PROXY_CLIENT', language : 'cpp')
+endif
+if get_option('proxy_server').enabled()
+    opendht_src += 'src/dht_proxy_server.cpp'
+    add_project_arguments('-DOPENDHT_PROXY_SERVER', language : 'cpp')
+endif
+if get_option('peer_discovery').enabled()
+    opendht_src += 'src/peer_discovery.cpp'
+    add_project_arguments('-DOPENDHT_PEER_DISCOVERY', language : 'cpp')
+endif
+opendht = shared_library('opendht',
+    opendht_src, 
+    include_directories : opendht_inc,
+    dependencies : deps,
+    cpp_args : ['-DOPENHT_BUILD', '-Dopendht_EXPORTS'])
+
+readline = meson.get_compiler('c').find_library('readline')
+dhtnode = executable('dhtnode', 'tools/dhtnode.cpp', link_with : opendht, dependencies : [readline, msgpack])

meson_options.txt

+option('proxy_client', type : 'feature', value : 'disabled')
+option('proxy_server', type : 'feature', value : 'disabled')
+option('peer_discovery', type : 'feature', value : 'enabled')