Known configuration

ndk.dir=/home/.../Sdk/ndk-bundle  
sdk.dir=/home/.../Sdk  

Gradlew compilation error

Execution failed for task ':app:transformNativeLibsWithStripDebugSymbolForxxxxx'.
> A problem occurred starting process 'command '\
<sdk.dir>/ndk-bundle/toolchains/mips64el-linux-android-4.9/prebuilt/linux-x86_64/bin/mips64el-linux-android-strip''

View Android/SDK installation path

$ ll <sdk.dir>/ndk-bundle/toolchains/
drwxrwxrwx  3 lily lily 4096 aarch64-linux-android-4.9/
drwxrwxrwx  3 lily lily 4096 arm-linux-androideabi-4.9/
drwxrwxrwx  3 lily lily 4096 llvm/
lrwxrwxrwx  1 lily lily   25 mips64el-linux-android-4.9 -> aarch64-linux-android-4.9/
lrwxrwxrwx  1 lily lily   25 mipsel-linux-android-4.9 -> arm-linux-androideabi-4.9/
drwxrwxrwx  3 lily lily 4096 renderscript/
drwxrwxrwx  3 lily lily 4096 x86-4.9/
drwxrwxrwx  3 lily lily 4096 x86_64-4.9/

I downloaded an extra version of NDK R15, android-ndk-r15c

To change to

$ ll <sdk.dir>/ndk-bundle/toolchains/
drwxrwxrwx  3 lily lily 4096 aarch64-linux-android-4.9/
drwxrwxrwx  3 lily lily 4096 arm-linux-androideabi-4.9/
drwxrwxrwx  3 lily lily 4096 llvm/
lrwxrwxrwx  1 lily lily 84 mips64el-linux-android-4.9 -> <sdk.dir>/ndk/android-ndk-r15c/toolchains/mips64el-linux-android-4.9/
lrwxrwxrwx  1 lily lily 82 mipsel-linux-android-4.9 -> <sdk.dir>/ndk/android-ndk-r15c/toolchains/mipsel-linux-android-4.9/
drwxrwxrwx  3 lily lily 4096 renderscript/
drwxrwxrwx  3 lily lily 4096 x86-4.9/
drwxrwxrwx  3 lily lily 4096 x86_64-4.9/

In this way, there is no error in compilation

No toolchains found in the NDK toolchains folder for ABI with prefix