Minimal project that uses autoconf and automake to demonstrate an issue with android ndk r23, see android/ndk#1614.
To test:
git clone https://github.com/grimler91/minimal-ndk-r23-issue-example
cd minimal-ndk-r23-issue-example
aclocal
libtoolize --copy
autoconf
automake --add-missing --foreign
# Adjust for path to your ndk
TOOLCHAINROOT=/opt/android-ndk/toolchains/llvm/prebuilt/linux-x86_64
CCPREFIX=$TOOLCHAINROOT/bin/aarch64-linux-android28-
# Optimization level seem to make a difference
CXXFLAGS=-O0 CXX=${CCPREFIX}clang++ CC=${CCPREFIX}clang ./configure --host=aarch64-linux-android --prefix=$(pwd)
make
make install
# Push compiled program, library and libc++_shared to device
adb push bin/main lib/libtest.so $TOOLCHAINROOT/sysroot/usr/lib/aarch64-linux-android/libc++_shared.so /data/local/tmp/
# Try to run the program on device:
adb shell
$ cd /data/local/tmp
$ LD_PRELOAD=./libtest.so:./libc++_shared.so ./main
You should get something like:
WARNING: linker: Warning: "/data/local/tmp/libc++_shared.so" unused DT entry: unknown processor-specific (type 0x70000001 arg 0x0) (ignoring)
CANNOT LINK EXECUTABLE "./main": cannot locate symbol "__extenddftf2" referenced by "/data/local/tmp/libtest.so"...
Where the missing __extenddftf2 symbol comes from the use of
static_cast<long double> in test.cpp.
If the project is compiled with cmake instead:
CXXFLAGS=-O0 CXX=${CCPREFIX}clang++ CC=${CCPREFIX}clang cmake .
make
then the resulting library and program work fine.