Ports: Add PrBoom+

Music (MIDI) works through TiMidity++ and OpenGL support works, but is
still very buggy. Sometimes PrBoom+ fails to load its own configuration
file, which can be worked around by deleting it.

Ports/prboom-plus/patches/0001-Remove-WAD-data-targets-from-build.patch

@@ -0,0 +1,46 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Jelle Raaijmakers <jelle@gmta.nl>
+Date: Thu, 1 Sep 2022 12:05:29 +0200
+Subject: [PATCH] Remove WAD / data targets from build
+
+We're crosscompiling but PRBoom+ still tries to invoke the rdatawad
+tool, which we're supposed to get from a different native build.
+
+We download the PRBoom WAD separately, so we remove it from the build.
+---
+ CMakeLists.txt     | 2 --
+ src/CMakeLists.txt | 1 -
+ 2 files changed, 3 deletions(-)
+
+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index 55e1573..540c85c 100644
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -215,7 +215,6 @@ endif()
+ 
+ if(CMAKE_CROSSCOMPILING)
+     set(IMPORT_EXECUTABLES "IMPORTFILE-NOTFOUND" CACHE FILEPATH "Export file from native build")
+-    include(${IMPORT_EXECUTABLES})
+ else()
+     if(NOT CROSS_EXPORTS)
+         set(CROSS_EXPORTS "")
+@@ -227,7 +226,6 @@ set(PRBOOM_OUTPUT_PATH ${CMAKE_BINARY_DIR})
+ set(WAD_DATA prboom-plus.wad)
+ set(WAD_DATA_PATH "${PRBOOM_OUTPUT_PATH}/${WAD_DATA}")
+ 
+-add_subdirectory(data)
+ add_subdirectory(doc)
+ add_subdirectory(src)
+ 
+diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
+index 627ef88..ae3599b 100644
+--- a/src/CMakeLists.txt
++++ b/src/CMakeLists.txt
+@@ -374,7 +374,6 @@ function(AddGameExecutable TARGET SOURCES)
+         target_include_directories(${TARGET} PRIVATE ${ALSA_INCLUDE_DIR})
+         target_link_libraries(${TARGET} PRIVATE ${ASOUND_LIBRARY})
+     endif()
+-    add_dependencies(${TARGET} prboomwad)
+ 
+     if(MSVC)
+         set_target_properties(${TARGET} PROPERTIES

Ports/prboom-plus/patches/ReadMe.md

@@ -0,0 +1,11 @@
+# Patches for prboom-plus on SerenityOS
+
+## `0001-Remove-WAD-data-targets-from-build.patch`
+
+Remove WAD / data targets from build
+
+We're crosscompiling but PRBoom+ still tries to invoke the rdatawad
+tool, which we're supposed to get from a different native build.
+
+We download the PRBoom WAD separately, so we remove it from the build.
+