linux: add a Flatpak manifest

This manifest will build a Flatpak from the current local source
directory.

build-aux/flatpak/README.md

@@ -0,0 +1,31 @@
+# Flatpak Build Instructions
+
+## Prerequisites
+To build the Flatpak, install the `flatpak` and `flatpak-builder` packages
+from your repositories. Then, [add Flathub](https://flatpak.org/setup/).
+
+Now, install the KDE SDK:
+```sh
+flatpak install flathub org.kde.Sdk//5.15-22.08
+```
+
+## Building and installing
+To build and install the app locally:
+
+```sh
+flatpak-builder --force-clean --install --user builddir build-aux/flatpak/org.thentrythis.Samplebrain.yaml
+```
+
+## Building and exporting
+To build and export a Flatpak bundle:
+
+```sh
+flatpak-builder --force-clean --repo=repo builddir build-aux/flatpak/org.thentrythis.Samplebrain.yaml
+flatpak build-bundle repo org.thentrythis.Samplebrain.flatpak org.thentrythis.Samplebrain
+```
+
+To install the bundle:
+
+```sh
+flatpak install org.thentrythis.Samplebrain.flatpak
+```

build-aux/flatpak/org.thentrythis.Samplebrain.yaml

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+id: org.thentrythis.Samplebrain
+runtime: org.kde.Platform
+runtime-version: "5.15-22.08"
+sdk: org.kde.Sdk
+
+rename-desktop-file: samplebrain.desktop
+rename-icon: samplebrain
+
+command: samplebrain
+
+finish-args:
+  - "--share=ipc"
+  - "--socket=wayland"
+  - "--socket=fallback-x11"
+  - "--socket=pulseaudio"
+  - "--device=dri"
+  - "--share=network"
+
+cleanup:
+  - "/include"
+  - "/lib/cmake"
+  - "/lib/pkgconfig"
+  - "/share/doc"
+
+modules:
+  - name: libsndfile
+    buildsystem: cmake-ninja
+    config-opts:
+      - "-DCMAKE_BUILD_TYPE=Release"
+      - "-DBUILD_SHARED_LIBS=ON"
+      - "-DENABLE_EXTERNAL_LIBS=NO"
+      - "-DENABLE_CPACK=NO"
+      - "-DBUILD_PROGRAMS=OFF"
+      - "-DBUILD_EXAMPLES=OFF"
+    sources:
+      - type: archive
+        url: https://github.com/libsndfile/libsndfile/releases/download/1.1.0/libsndfile-1.1.0.tar.xz
+        sha256: 0f98e101c0f7c850a71225fb5feaf33b106227b3d331333ddc9bacee190bcf41
+
+  - name: portaudio
+    buildsystem: autotools
+    config-opts:
+      - "--with-alsa"
+      - "--without-jack"
+      - "--without-oss"
+      - "--without-asihpi"
+    sources:
+      - type: archive
+        url: http://files.portaudio.com/archives/pa_stable_v190700_20210406.tgz
+        sha256: 47efbf42c77c19a05d22e627d42873e991ec0c1357219c0d74ce6a2948cb2def
+
+  - name: liblo
+    buildsystem: autotools
+    config-opts:
+      - "--disable-tests"
+      - "--disable-network-tests"
+      - "--disable-tools"
+      - "--disable-examples"
+    sources:
+      - type: archive
+        url: https://versaweb.dl.sourceforge.net/project/liblo/liblo/0.31/liblo-0.31.tar.gz
+        sha256: 2b4f446e1220dcd624ecd8405248b08b7601e9a0d87a0b94730c2907dbccc750
+
+  - name: samplebrain
+    buildsystem: qmake
+    build-options:
+      env:
+        PREFIX: /app
+    config-opts:
+      - "LIBS+=-L/app/lib"
+    sources:
+      - type: dir
+        path: ../../