Ports: Add libpng 1.6.37

Author: https://github.com/TheMorc
Commit: https://github.com/SerenityOS/serenity/commit/538975b713a
Pull-request: https://github.com/SerenityOS/serenity/pull/5626

Ports/AvailablePorts.md

@@ -36,6 +36,7 @@ Please make sure to keep this list up to date when adding and updating ports. :^
 | [`libffi`](libffi/)            | libffi                                        | 3.3               | https://www.sourceware.org/libffi/                    |
 | [`libiconv`](libiconv/)        | GNU libiconv                                  | 1.16              | https://www.gnu.org/software/libiconv/                |
 | [`libjpeg`](libjpeg/)          | libjpeg                                       | 9d                | https://ijg.org/                                      |
+| [`libpng`](libpng/)            | libpng                                        | 1.6.37            | https://libpng.org/                                   |
 | [`libpuffy`](libpuffy/)        | libpuffy                                      | 1.0               | https://github.com/ibara/libpuffy                     |
 | [`libtiff`](libtiff/)          | libtiff                                       | 4.2.0             | http://www.libtiff.org/                               |
 | [`links`](links/)              | Links web browser                             | 2.19              | http://links.twibright.com/                           |

Ports/libpng/package.sh

@@ -0,0 +1,6 @@
+#!/usr/bin/env -S bash ../.port_include.sh
+port=libpng
+version=1.6.37
+useconfigure=true
+files="https://download.sourceforge.net/libpng/libpng-${version}.tar.gz libpng-${version}.tar.gz"
+workdir="libpng-$version"

Ports/libpng/patches/detect.patch

@@ -0,0 +1,11 @@
+--- config.sub	2021-03-03 22:42:25.065684142 +0100
++++ libpng-1.6.37/config.sub	2021-03-03 22:43:50.611720741 +0100
+@@ -1390,7 +1390,7 @@
+ 	      | -powermax* | -dnix* | -nx6 | -nx7 | -sei* | -dragonfly* \
+ 	      | -skyos* | -haiku* | -rdos* | -toppers* | -drops* | -es* \
+ 	      | -onefs* | -tirtos* | -phoenix* | -fuchsia* | -redox* | -bme* \
+-	      | -midnightbsd*)
++	      | -midnightbsd* | -serenity*)
+ 	# Remember, each alternative MUST END IN *, to match a version number.
+ 		;;
+ 	-qnx*)