build: Add support for flatpaks

Based on the original work of @Calinou

.github/workflows/build.yml

@@ -12,6 +12,9 @@ jobs:
   linux:
     runs-on: ubuntu-20.04
     name: 🐧 Ubuntu 20.04
+    container:
+      image: bilelmoussaoui/flatpak-github-actions:gnome-40
+      options: --privileged
     steps:
 
     - name: 🧰 Checkout
@@ -39,6 +42,13 @@ jobs:
           ..
         make -j 4 install
 
+    - name: ✋ Bundle Flatpak
+      uses: bilelmoussaoui/flatpak-github-actions/flatpak-builder@v4
+      with:
+        bundle: imhex.flatpak
+        manifest-path: dist/net.werwolv.ImHex.yaml
+        cache-key: flatpak-builder-${{ github.sha }}
+
     - name: 📦 Upload ELF
       uses: actions/upload-artifact@v2
       with:
@@ -46,6 +56,13 @@ jobs:
         path: |
           build/install/*
 
+    - name: 📦 Upload Flatpak
+      uses: actions/upload-artifact@v2
+      with:
+        name: Linux Flatpak
+        path: |
+          build/*.flatpak
+
   win:
     runs-on: windows-latest
     name: 🟦 Windows MINGW64

dist/net.werwolv.ImHex.yaml

@@ -0,0 +1,71 @@
+app-id: net.werwolv.ImHex
+runtime: org.freedesktop.Platform
+runtime-version: '20.08'
+default-branch: stable
+sdk: org.freedesktop.Sdk
+command: imhex
+
+finish-args:
+  - --share=ipc
+  - --socket=x11
+  - --filesystem=host
+  - --device=all
+
+modules:
+  - name: capstone
+    buildsystem: cmake-ninja
+    builddir: true
+    config-opts:
+      - -DCMAKE_BUILD_TYPE=RelWithDebInfo
+    sources:
+      - type: archive
+        url: https://github.com/aquynh/capstone/archive/4.0.2.tar.gz
+        sha256: 7c81d798022f81e7507f1a60d6817f63aa76e489aa4e7055255f21a22f5e526a
+
+  - name: libiconv
+    sources:
+      - type: archive
+        url: https://ftp.gnu.org/pub/gnu/libiconv/libiconv-1.16.tar.gz
+        sha256: e6a1b1b589654277ee790cce3734f07876ac4ccfaecbee8afa0b649cf529cc04
+
+  - name: glfw
+    buildsystem: cmake-ninja
+    builddir: true
+    config-opts:
+      - -DCMAKE_BUILD_TYPE=RelWithDebInfo
+      - -DBUILD_SHARED_LIBS:BOOL=ON
+    sources:
+      - type: archive
+        url: https://github.com/glfw/glfw/releases/download/3.3.2/glfw-3.3.2.zip
+        sha256: 08a33a512f29d7dbf78eab39bd7858576adcc95228c9efe8e4bc5f0f3261efc7
+    cleanup:
+      - /include
+      - /lib/pkgconfig
+
+  - name: mbedtls
+    buildsystem: cmake-ninja
+    config-opts:
+      - -DCMAKE_C_FLAGS=-fPIC
+    sources:
+      - type: archive
+        url: https://github.com/ARMmbed/mbedtls/archive/refs/tags/v2.27.0.tar.gz
+        sha256: 2a07856e541f0e5f6eaee4f78018c52f25bd244ed76f9020dea54a8b02cac6ea
+
+  - name: nlohmann-json
+    buildsystem: cmake-ninja
+    builddir: true
+    config-opts:
+      - -DCMAKE_BUILD_TYPE=RelWithDebInfo
+      - -DBUILD_TESTING=OFF
+
+    sources:
+      - type: archive
+        url: https://github.com/nlohmann/json/archive/v3.9.1.tar.gz
+        sha256: 4cf0df69731494668bdd6460ed8cb269b68de9c19ad8c27abc24cd72605b2d5b
+
+  - name: imhex
+    buildsystem: cmake-ninja
+
+    sources:
+      - type: git
+        url: https://github.com/WerWolv/ImHex.git