CMake fails to find C and C++ compiler if the specified toolchain is clang

[void-etoile]

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Description

If trying to build with the NDK and cmake as described here:

https://cmake.org/cmake/help/v3.7/manual/cmake-toolchains.7.html#id20

it will work when using GCC as the toolchain but fails with clang (paths to the clang C and C++ compilers will be malformed). e.g.:

/Users/james/Downloads/android-ndk-r16-beta2/toolchains//prebuilt/darwin-x86_64/bin/clang is not a full path to an existing compiler tool.

Notice the missing "llvm" in the path. This can be reproduced with r15c and r16 Beta 2.

I attach a minimal test case that will repro the problem if you open a terminal in the root folder and run the following command:

cmake -DCMAKE_TOOLCHAIN_FILE=./toolchain.cmake ./

Please note you will have to set the path to your NDK in the .toolchain file as I obviously cannot guess where the NDK is on your hard drive.

ndk_repro.zip

Environment Details

• NDK Version: r15c or r16 Beta 2
• Build sytem: cmake 3.7 or later
• Host OS: Tested on both Mac & Windows
• Compiler: clang
• ABI: arm64-v8a
• STL: NA
• NDK API level: 21
• Device API level: NA

[void-etoile]

I just saw in #504 that this is fixed with CMake 3.9.2 and above. Confirm it works with 3.9.5.