The new toolchain file requires Android NDK r12b and above. Default to use 'arm-linux-androideabi-clang' toolchain and LLVM libc++ STL runtime.
Align all the compiler and linker flags according to new ndk-build configuration in Android NDK r12b, i.e. no more '-f[no-]strict-aliasing' and '-f[no-]omit-frame-pointer', but more stringent warnings check.
Improve over the old toolchain file where most of the options are now changeable after the initial configuration. The exceptions are ANDROID_NDK and ANDROID_TOOLCHAIN_NAME due to limitation of CMake.
Close#1441.
Other changes in this commit includes:
- Fix Android sample launcher app to support shared C++ STL runtime library.
- Remove temporary fix in FindUrho3D module as it is not required anymore with our new toolchain file.
- Fix Log::WriteRaw() method to pass the parameters correctly to __android_log_print() function.
- Fix enable_pch() macro to emit -fPIC compiler flags correctly based on target's POSITION_INDEPENDENT_CODE property.
- Fix linker flags for ld.bfd where it needs help to find the location of the rooted shared libraries. The flags are not required for ld.gold but they do no harm for gold linker.
- Enhance the CheckCompilerToolchain module to auto-detect if the NEON SIMD is enabled or not for Android build (based on the chosen ANDROID_ABI).
When cross-compiling we have already defined '--sysroot' to find the direct library dependencies. However when a shared library has its own dependencies (DT_NEEDED) then we need to supply extra linker flags to help the linker to find those indirect library dependecies in the sysroot.
Actually we also had this problem for 32-bit ARM cross-compiling, but we cheated in the earlier CI build jobs by using Linaro/Raspbian compiler toolchain. Somehow the Raspbian's linker simply "ignores" those indirect library dependencies or it uses other mean to locate them (but I doubt that), and so it does not have linker issues with libreadline.so (depends on tinfo), libGLESv2.so (depends on glapi), etc. The other ARM compiler toolchains from Linaro seem to be more strict in this regard. Most likely the raspbian's linker is a gold linker.
This commit could also potentially fix a known issue in our FindUrho3D.cmake module where we have to hardcode the library dependencies that libUrho3D.so in turn depends on (to be investigated later).
Add a new build option "ARM_ABI_FLAGS" for supplying additional ABI compiler flags when targeting generic arm.
Fix Linux build from using OpenGLES instead of GLEW, fix RPI build from using wrong OpenGLES library, fix iOS build from using arm-specific compiler flags directly which would cause problem in universal binary build containing iphonesimulator archs as well.
And other minor refactoring.
Check the CMake minimum version before setting project name as recommended by CMake.
Minor documentation update on how to setup downstream projects using Urho3D library as external library.
For AppVeyor - attempt to add scaffolding test using Urho3D SDK.
