gnu: asio: Update to 1.18.1.

* gnu/packages/networking.scm (asio): Update to 1.18.1.
(asio-1.12): New variable.
* gnu/packages/emulators.scm (mame)[inputs]: Use asio-1.12, otherwise it fails
to build.

gnu/packages/emulators.scm

@@ -1743,7 +1743,7 @@ (define-public mame
        ("texinfo" ,texinfo)))
     (inputs
      `(("alsa-lib" ,alsa-lib)
-       ("asio" ,asio)
+       ("asio" ,asio-1.12)              ;the bundled copy is at 1.11
        ("expat" ,expat)
        ("flac" ,flac)
        ("fontconfig" ,fontconfig)

gnu/packages/networking.scm

@@ -26,7 +26,7 @@
 ;;; Copyright © 2018, 2020 Marius Bakke <mbakke@fastmail.com>
 ;;; Copyright © 2018, 2020 Oleg Pykhalov <go.wigust@gmail.com>
 ;;; Copyright © 2018 Pierre Neidhardt <mail@ambrevar.xyz>
-;;; Copyright © 2019, 2020 Maxim Cournoyer <maxim.cournoyer@gmail.com>
+;;; Copyright © 2019, 2020, 2021 Maxim Cournoyer <maxim.cournoyer@gmail.com>
 ;;; Copyright © 2019 Vasile Dumitrascu <va511e@yahoo.com>
 ;;; Copyright © 2019 Julien Lepiller <julien@lepiller.eu>
 ;;; Copyright © 2019 Timotej Lazar <timotej.lazar@araneo.si>
@@ -3027,7 +3027,8 @@ (define-public can-utils
     ;; Either BSD-3 or GPL-2 can be used.
     (license (list license:bsd-3 license:gpl2))))
 
-(define-public asio
+;;; This is an old version required by rested.
+(define-public asio-1.12
   (package
     (name "asio")
     (version "1.12.2")
@@ -3054,6 +3055,18 @@ (define-public asio
 asynchronous model using a modern C++ approach.")
     (license license:boost1.0)))
 
+(define-public asio
+  (package
+    (inherit asio-1.12)
+    (version "1.18.1")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (string-append "mirror://sourceforge/asio/asio/"
+                           version " (Stable)/asio-" version ".tar.bz2"))
+       (sha256
+        (base32 "04wi69d72l1p5c7d63z1dz06zn8pdqsbgx1if98dszs9ymfqgyaa"))))))
+
 (define-public shadowsocks
   ;; There are some security fixes after the last release.
   (let* ((commit "e332ec93e9c90f1cbee676b022bf2c5d5b7b1239")