Integrate android openssl fetch support

CMakeLists.txt

@@ -43,10 +43,17 @@ find_package(Qt6 REQUIRED COMPONENTS
     Nfc
 )
 
+find_package(OpenSSL QUIET)
+
 if(ANDROID)
-    find_package(OpenSSL REQUIRED)
-else()
-    find_package(OpenSSL QUIET)
+    include(FetchContent)
+    FetchContent_Declare(
+        android_openssl
+        DOWNLOAD_EXTRACT_TIMESTAMP true
+        URL https://github.com/KDAB/android_openssl/archive/refs/heads/master.zip
+    )
+    FetchContent_MakeAvailable(android_openssl)
+    include(${android_openssl_SOURCE_DIR}/android_openssl.cmake)
 endif()
 
 # Make config.h available to all targets

README.md

@@ -35,13 +35,13 @@ Optional configuration flags to be passed to qmake:
 > Enables building the testrunner target
 
 ## Android
-When targeting Android, make sure a cross-compiled build of OpenSSL is
-available to CMake (for example by setting `OPENSSL_ROOT_DIR` when
-configuring). The CMake build will automatically package the resolved
-`libssl` and `libcrypto` shared libraries inside the Android bundle, following
-the Qt for Android OpenSSL deployment guidelines. Other platforms will build
-without explicitly linking to OpenSSL if the development package is not
-installed.
+When targeting Android, the build will download the KDAB
+[`android_openssl`](https://github.com/KDAB/android_openssl) package at
+configure time and automatically bundle the provided `libssl` and `libcrypto`
+shared libraries inside the APK. An active internet connection is therefore
+required the first time you configure an Android build directory. Other
+platforms will build without explicitly linking to OpenSSL if the development
+package is not installed.
 
 ## Windows
 

libnymea-app/CMakeLists.txt

@@ -99,8 +99,6 @@ target_link_libraries(nymea-app-core
 
 if(TARGET OpenSSL::SSL AND TARGET OpenSSL::Crypto)
     target_link_libraries(nymea-app-core PUBLIC OpenSSL::SSL OpenSSL::Crypto)
-elseif(ANDROID)
-    message(FATAL_ERROR "OpenSSL libraries are required for Android builds but were not found.")
 else()
     message(WARNING "OpenSSL development libraries not found; continuing without explicit OpenSSL linkage.")
 endif()

nymea-app/CMakeLists.txt

@@ -111,15 +111,3 @@ if(WIN32)
     target_compile_definitions(nymea-app PRIVATE NOMINMAX)
 endif()
 
-if(ANDROID)
-    if(TARGET OpenSSL::SSL AND TARGET OpenSSL::Crypto)
-        # Ship the OpenSSL shared libraries inside the Android package as
-        # described in the Qt documentation so SSL works out of the box.
-        set_property(TARGET nymea-app APPEND PROPERTY QT_ANDROID_EXTRA_LIBS
-            $<TARGET_FILE:OpenSSL::SSL>
-            $<TARGET_FILE:OpenSSL::Crypto>
-        )
-    else()
-        message(WARNING "OpenSSL libraries not available; the Android package will miss SSL support.")
-    endif()
-endif()