Cross compile to ARM target with latest Github

[Iwbnwif Yiw]

Hi,

The current official version of wxWidgets (3.0.3) cross compiles to an ARM target (Raspberry Pi 3) with no problems.

However, recent Github 3.1.0 versions have some problems.

I used buildroot to create the cross compile environment on Ubuntu 16.04, exactly the same environment for both versions of wxWidgets. The process is more or less as described here: http://yasriady.blogspot.co.uk/2015/10/how-to-build-wxwidgets-for-raspberry-pi.html

Initially for configure I used:

../../configure --host=arm-linux --with-gtk --with-libpng=builtin --with-libjpeg=builtin --with-libtiff=builtin --with-regex=builtin --with-zlib=builtin --with-expat=builtin LDFLAGS="-static-libgcc -static-libstdc++" --disable-shared

The 3.1.0 libraries also build fine with this config, however if I try to build the 'minimal' sample, the following occurs:

undefined reference to `png_init_filter_functions_neon'

A quick Google shows that this may be caused by the setup in pngpriv.h. I wonder if change 54126d5 might have anything to do with it?

A work around is to not use the built in libpng, i.e. change configure to be:

../../configure --host=arm-linux --with-gtk --with-libjpeg=builtin --with-libtiff=builtin --with-regex=builtin --with-zlib=builtin --with-expat=builtin LDFLAGS="-static-libgcc -static-libstdc++"  --disable-shared

The second problem is when I try to run minimal I get: version `GLIBC_2.25' not found (required by ./minimal)

I suspect this is to do with the difference in libraries created by buildroot and installed by Raspbian, but wanted to check if there is any reason why the 3.1.0 needs a newer version of libc.so?

TIA!