[cmake, docs] msys: allow bundled FFmpeg, update dep/caveat docs, faster linking on Release mode (#2921)

Signed-off-by: crueter <crueter@eden-emu.dev>
Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/2921
Reviewed-by: Caio Oliveira <caiooliveirafarias0@gmail.com>
Reviewed-by: Lizzie <lizzie@eden-emu.dev>

docs/Caveats.md

@@ -13,12 +13,11 @@
 
 ## Arch Linux
 
-- httplib AUR package is broken. Set `httplib_FORCE_BUNDLED=ON` if you have it installed.
-- Eden is also available as an [AUR package](https://aur.archlinux.org/packages/eden-git). If you are unable to build, either use that or compare your process to the PKGBUILD.
+Eden is also available as an [AUR package](https://aur.archlinux.org/packages/eden-git). If you are unable to build, either use that or compare your process to the PKGBUILD.
 
 ## Gentoo Linux
 
-Do not use the system sirit or xbyak packages.
+Enable the GURU repository to install [`games-emulation/eden`](https://gitweb.gentoo.org/repo/proj/guru.git/tree/games-emulation/eden). This repository also contains some additional dependencies, such as mcl, sirit, oaknut, etc.
 
 ## macOS
 
@@ -102,3 +101,60 @@ cmake -B build -DCMAKE_BUILD_TYPE=Release
 cmake --build build -- -j`nproc`
 cmake --install build
 ```
+
+## MSYS2
+
+`qt6-static` isn't supported yet.
+
+Only the `MINGW64` environment is tested; however, all of the others should work (in theory) sans `MINGW32`.
+
+Currently, only FFmpeg can be used as a system dependency; the others will result in linker errors.
+
+When packaging an MSYS2 build, you will need to copy all dependent DLLs recursively alongside the `windeployqt6`; for example:
+
+```sh
+# MSYS_TOOLCHAIN is typically just mingw64
+# since Windows is case-insensitive, you can set this to $MSYSTEM
+# or, if cross-compiling from Linux, set it to usr/x86_64-w64-mingw32
+export PATH="/${MSYS_TOOLCHAIN}/bin:$PATH"
+
+# grab deps of a dll or exe and place them in the current dir
+deps() {
+    # string parsing is fun
+    objdump -p "$1" | grep -e ".DLL Name:" | cut -d" " -f3 | while read -r dll; do
+        [ -z "$dll" ] && continue
+
+        # bin directory is used for DLLs, so we can do a quick "hack"
+        # and use command to find the path of the DLL
+        dllpath=$(command -v "$dll" 2>/dev/null || true)
+
+        [ -z "$dllpath" ] && continue
+
+        # explicitly include system32/syswow64 deps
+        # these aren't needed to be bundled, as all systems include them
+        case "$dllpath" in
+            *System32* | *SysWOW64*) continue ;;
+        esac
+
+        # avoid copying deps multiple times
+        if [ ! -f "$dll" ]; then
+            echo "$dllpath"
+            cp "$dllpath" "$dll"
+
+            # also grab the dependencies of the dependent DLL; e.g.
+            # double-conversion is a dep of Qt6Core.dll but NOT eden.exe
+            deps "$dllpath"
+        fi
+    done
+}
+
+# NB: must be done in a directory containing eden.exe
+deps eden.exe
+
+# deploy Qt plugins and such
+windeployqt6 --release --no-compiler-runtime \
+  --no-opengl-sw --no-system-dxc-compiler --no-system-d3d-compiler eden.exe
+
+# grab deps for Qt plugins
+find ./*/ -name "*.dll" | while read -r dll; do deps "$dll"; done
+```

docs/Deps.md

@@ -87,6 +87,15 @@ Notes for writers: Include build tools as well, assume user has NOTHING installe
 
 Click on the arrows to expand.
 
+<details>
+<summary>Gentoo Linux</summary>
+
+GURU must be enabled:
+
+```
+sudo
+</details>
+
 <details>
 <summary>Arch Linux</summary>
 
@@ -149,6 +158,8 @@ apk add g++ git cmake make mbedtls-dev mbedtls-static mesa-dev qt6-qtbase-dev qt
 `mbedtls-static` has to be specified otherwise `libeverest.a` and `libp256m.a` will fail to be found.
 
 </details>
+
+<details>
 <summary>Void Linux</summary>
 
 ```sh
@@ -158,6 +169,7 @@ xbps-install -Su git make cmake clang pkg-config patch mbedtls-devel SPIRV-Tools
 Yes, `nlohmann-json` is just named `json-c++`. Why?
 
 </details>
+
 <details>
 <summary>NixOS</summary>
 
@@ -234,24 +246,27 @@ Then install the libraries: `sudo pkg install qt6 boost glslang libzip library/l
 * Download and install all dependencies:
 ```
 BASE="git make autoconf libtool automake-wrapper jq patch"
-MINGW="SDL2 cmake python-pip qt6-base toolchain ffmpeg boost catch fmt lz4 nlohmann-json openssl zlib zstd enet opus mbedtls vulkan-devel libusb vulkan-memory-allocator unordered_dense clang ccache"
+
+MINGW="qt6-base qt6-tools qt6-translations qt6-svg cmake toolchain clang python-pip openssl vulkan-memory-allocator vulkan-devel glslang boost fmt lz4 nlohmann-json zlib zstd enet opus mbedtls libusb unordered_dense"
 
 packages="$BASE"
 for pkg in $MINGW; do
     packages="$packages mingw-w64-x86_64-$pkg"
 done
 
-pacman -Syu --needed --noconfirm $packages
+pacman -Syuu --needed --noconfirm $packages
 ```
 * Notes:
   - Using `qt6-static` is possible but currently untested.
   - Other environments are entirely untested, but should theoretically work provided you install all the necessary packages.
-  - Clang is installed as it generally works better here. You can compile with GCC just fine, however.
+  - GCC is proven to work better with the MinGW environment. If you choose to use Clang, you *may* be better off using the clang64 environment.
   - Add `qt-creator` to the `MINGW` variable to install Qt Creator. You can then create a Start Menu shortcut to the MinGW Qt Creator by running `powershell "\$s=(New-Object -COM WScript.Shell).CreateShortcut('C:\\ProgramData\\Microsoft\\Windows\\Start Menu\\Programs\\Qt Creator.lnk');\$s.TargetPath='C:\\msys64\\mingw64\\bin\\qtcreator.exe';\$s.Save()"` in Git Bash or MSYS2.
 * Add MinGW binaries to the PATH if they aren't already:
   * `echo 'PATH=/mingw64/bin:$PATH' >> ~/.bashrc`
   * or `echo 'PATH=/mingw64/bin:$PATH' >> ~/.zshrc`
 
+[Caveats](./Caveats.md#msys2).
+
 </details>
 <details>
 <summary>HaikuOS</summary>
@@ -263,6 +278,8 @@ pkgman install git cmake patch libfmt_devel nlohmann_json lz4_devel opus_devel b
 [Caveats](./Caveats.md#haikuos).
 
 </details>
+
+<details>
 <summary>RedoxOS</summary>
 
 TODO: Fix syscall crashes (heavy IO stalls and hangup due to net mutexes?)