[build][CMake] Unable to build raylib as a shared library for Android

[OussamaTeyib]

• I tested it on the latest Raylib version from the master branch
• I checked there is no similar issue already reported (in the Android section)
• I checked the documentation on the wiki

---

Issue description
I encountered a linker error when building Raylib as a shared library for Android using the provided CMake configuration.The error indicates an "undefined symbol: main" when trying to link the Raylib shared library.


Since Android requires native applications to have an android_main() entry, Raylib's implementation allows the user to define a main() function, which is then called by Raylib. This must be taken into account by the build system.

Steps to reproduce

1. Use the provided Raylib CMake build system for Android (configured with the Android NDK).

2. Run the following CMake command to configure the build:

   cmake -B Build -DCMAKE_TOOLCHAIN_FILE=%ANDROID_NDK_HOME%\build\cmake\android.toolchain.cmake -DANDROID_ABI=arm64-v8a -DANDROID_PLATFORM=android-35 -DPLATFORM=Android -DBUILD_EXAMPLES=OFF -DCMAKE_BUILD_TYPE=Release -DBUILD_SHARED_LIBS=ON -G Ninja
   

3. Build the shared library:

   cmake --build build
   

4. Encounter the linker error during the linking step:

   ld.lld: error: undefined symbol: main
   >>> referenced by rcore_android.c:279 (C:/coding/raylib/raylib/src/platforms/rcore_android.c:279)
   >>>               raylib/CMakeFiles/raylib.dir/rcore.c.o:(android_main)
   clang: error: linker command failed with exit code 1 (use -v to see invocation)
   

Additional information

• This issue does not occur when using the provided Makefile, which works as expected.
• The problem seems to be related to the CMake configuration.
• The issue does not occur when building a static library.

Environment

• Raylib version: Latest master branch
• Operating System: Windows 10
• Android NDK version: r27b
• CMake version: 3.10.4

[raysan5]

Just note that I do not maintain the CMake build system...