flatpak: Add eigen module

pkg/flatpak/com.solvespace.SolveSpace.json

@@ -165,6 +165,27 @@
                 }
             ]
         },
+        {
+            "name": "eigen",
+            "buildsystem": "cmake-ninja",
+            "builddir": true,
+            "sources": [
+                {
+                    "type": "archive",
+                    "url": "https://gitlab.com/libeigen/eigen/-/archive/3.4.0/eigen-3.4.0.tar.gz",
+                    "sha256": "8586084f71f9bde545ee7fa6d00288b264a2b7ac3607b974e54d13e7162c1c72",
+                    "x-checker-data": {
+                        "type": "anitya",
+                        "project-id": 13751,
+                        "stable-only": true,
+                        "url-template": "https://gitlab.com/libeigen/eigen/-/archive/$version/eigen-$version.tar.gz"
+                    }
+                }
+            ],
+            "cleanup": [
+                "*"
+            ]
+        },
         {
             "name": "libjson-c",
             "buildsystem": "cmake-ninja",