p4a apk --private ~/Escritorio/proyectos-kivy/test --requirements=flask,python3 --bootstrap=webview --sdk_dir="/opt/android-sdk/" --android-api="27" --ndk_dir="/opt/crystax-ndk-10.3.2/" --package=com.fran.test --name="mi-test" --arch="armeabi-v7a" --ndk-api="21" --version=1.0

checking for arm-linux-androideabi-gcc... arm-linux-androideabi-gcc -DANDROID -fomit-frame-pointer -D__ANDROID_API__=21 -mandroid -I/opt/crystax-ndk-10.3.2/platforms/android-21/arch-arm -isysroot /opt/crystax-ndk-10.3.2/platforms/android-21/arch-arm -I/home/francisco/.local/share/python-for-android/build/python-installs/unnamed_dist_7/include/python3.7
checking whether the C compiler works... no
configure: error: in `/home/francisco/.local/share/python-for-android/build/other_builds/libffi/armeabi-v7a__ndk_target_21/libffi':
configure: error: C compiler cannot create executables
See `config.log' for more details