Ports: Update genemu's patches to use git patches

This required splitting the single patch file up, which was done with
_some_ degree of accuracy (but not entirely so).

Ports/genemu/patches/0001-Manually-link-against-SDL2.patch

@@ -0,0 +1,40 @@
+From 056b239a373a1ff7dafd50e75f5c08331d1fcb52 Mon Sep 17 00:00:00 2001
+From: aabajyan <arsen.abajyan@pm.me>
+Date: Sun, 7 Mar 2021 22:30:13 +0400
+Subject: [PATCH 1/5] Manually link against SDL2
+
+---
+ CMakeLists.txt | 18 ++++++++++++------
+ 1 file changed, 12 insertions(+), 6 deletions(-)
+
+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index 94ae8ef..a9a974c 100644
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -1,11 +1,17 @@
+ cmake_minimum_required(VERSION 2.6)
+-set(CMAKE_BUILD_TYPE "Debug")
+-
+ 
+ INCLUDE(FindPkgConfig)
+-PKG_SEARCH_MODULE(SDL2 REQUIRED sdl2)
+-INCLUDE_DIRECTORIES(${SDL2_INCLUDE_DIRS})
++find_package(SDL2 REQUIRED)
+ 
+-set_source_files_properties( mem.cpp PROPERTIES COMPILE_FLAGS " -O0 -UNDEBUG " )
++set_source_files_properties( mem.cpp PROPERTIES COMPILE_FLAGS " -Og")
+ add_executable(genemu genemu.cpp cpu.cpp vdp.cpp mem.cpp state.cpp gfx.cpp ioports.cpp hw.c Z80/Z80.c m68k/m68kcpu.c m68k/m68kops.c m68k/m68kopac.c m68k/m68kopdm.c m68k/m68kopnz.c m68k/m68kdasm.c ym2612/ym2612.c)
+-target_link_libraries(genemu ${SDL2_LIBRARIES})
++target_include_directories(genemu SYSTEM PRIVATE ${SDL2_INCLUDE_DIRS})
++
++if("${SDL2_LIBRARIES}" STREQUAL "")
++    message(WARNING "SDL2_LIBRARIES wasn't set, manually setting to SDL2::SDL2")
++    set(SDL2_LIBRARIES "SDL2::SDL2")
++endif()
++
++target_link_libraries(genemu PRIVATE ${SDL2_LIBRARIES})
++
++install(TARGETS genemu RUNTIME DESTINATION bin)
+-- 
+2.36.1
+