uClibc support

[speidy]

uClibc doesn't implement the dlinfo() and dladdr1() dl functions.
The existing Android solution fits for the uClibc case as well.

I’ve ran the test program locally when compiling with uClibc toolchain grabbed from: https://toolchains.bootlin.com.

I'll be happy if you can add the uClibc toolchain to the Travis CI system as well.

[kubo]

@speidy
Could you post the environment information you tested on? I failed to set up a uClibc environment to check your pull request.

I have a question.
Why features.h is included? It is a linux-specific header. It prevent compiling on other platforms.

[speidy]

Hi @kubo,

1. Regarding #include <features.h> - its redundant. Iv'e omitted this include now.
2. I've managed to test it in a chrooted environment by using the sysroot directory provided in the toolchain:
   2.1. Download x86_64 uclibc toolchain from the link iv'e provided (iv'e got x86-64-core-i7--uclibc--stable-2018.11-1)
   2.2. Export the toolchain's bin directory containing the gcc compiler to your $PATH. (e.g. export PATH=$PATH:~/toolchains/x86-64-core-i7--uclibc--stable-2018.11-1/bin).
   2.3. Build plthook tests while specifying the new compiler: make CC=x86_64-buildroot-linux-uclibc-gcc
   2.4. Now, change directory to the toolchain' sysroot directory, e.g.: ~/toolchains/x86-64-core-i7--uclibc--stable-2018.11-1/x86_64-buildroot-linux-uclibc/sysroot
   2.5. Now copy testprog to <sysroot>/usr/bin and libtest.so to <sysroot>/usr/lib.
   2.6. Now you also need to mount the procfs (as plthook using it): sudo mount -t proc none <sysroot>/proc
   2.6. now run the test binary under the chrooted sysroot: sudo chroot . ./usr/bin/testprog (run from sysroot directory)

Let me know if that works for you.

[kubo]

Thanks. I verified your code.
Merged.

[kubo]

Tests for uclibc support was added.
0a4c2a1

[speidy]

Thanks @kubo !