tce-load -i libpng-dev libjpeg-turbo-dev libXext-dev xorg-proto

cd fltk-1.1.10

use edited Fl_PNG_Image.cxx

http://lists.linuxtogo.org/pipermail/openembedded-devel/2012-December/043172.html

patch -Np1 -i ../fltk_libpng.patch

CC="gcc -flto -fuse-linker-plugin -mtune=generic -Os -pipe" CXX="g++ -flto -fuse-linker-plugin -mtune=generic -Os -pipe -fno-exceptions -fno-rtti" ./configure --prefix=/usr/local --enable-shared --disable-static --enable-threads --disable-gl

[upgrade tc-4.x -> 5.x]
sudo rm /usr/lib/libpng*
sudo ldconfig

make
sudo make install

-------------------------------------------------------------------------
    Directories: prefix=/usr/local
                 bindir=${exec_prefix}/bin
                 datadir=${datarootdir}
                 datarootdir=${prefix}/share
                 exec_prefix=${prefix}
                 includedir=${prefix}/include
                 libdir=${exec_prefix}/lib
                 mandir=${datarootdir}/man
       Graphics: X11
Image Libraries: JPEG=System
                 PNG=System
                 ZLIB=System
    Large Files: NO
         OpenGL: YES