如何本身編譯Qt，爲靜態編譯程序減小依賴方便發佈作準備

使用./configure -prefix /opt/Qt-5.6 -gstreamer 1.0  make  make install 編譯後，qml audio能夠播放mp3了，也就是qtmutimedia已經使用 gstreamer 1.0了，可是qml界面只能顯示英文，全部中文漢字都不顯示了。

靜態編譯命令： ./configure -static -prefix /opt/Qt-5.8-static -gstreamer 1.0 -fontconfig

./configure -prefix /opt/Qt-5.6 -gstreamer 1.0 -fontconfig

make -j4

FontConfig ............. no

sudo apt install libfontconfig1-dev
FontConfig ............. Yes

http://doc.qt.io/qt-5/qt-embedded-fonts.html

解釋：Qt normally uses fontconfig to provide access to system fonts. Iffontconfig is not available, e.g. in dedicated embedded systems where space is at a premium, Qt will fall back to using QBasicFontDatabase. In this case, Qt applications will look for fonts in Qt's lib/fonts/ directory. Qt will automatically detect prerendered fonts and TrueType fonts.

若是fontconfig 是 no，Qt就不能使用系統字體，只能使用lib/fonts 目錄下的字體，沒提供漢字字體，所以qml界面的漢字沒法顯示。

關於-qt-xcb選項的解釋：It's possible to configure Qt with -qt-xcb, which compiles in a set of xcb helper libraries instead of trying to link against the system versions. This can help make Qt less dependent on some of the xcb helper libraries that might not be available on all distributions. The table specifies which dependencies are provided by -qt-xcb. 資料來源：http://doc.qt.io/qt-5/linux-requirements.html

 

Ubuntu16.04 gcc5.4.0編譯Qt5.8 beta版時，以下錯誤

painting/qdrawhelper.cpp: In function ‘void blend_transformed_tiled_argb(int, const QSpan*, void*)’:
painting/qdrawhelper.cpp:4846:13: internal compiler error: Segmentation fault
 static void blend_transformed_tiled_argb(int count, const QSpan *spans, void *u

             ^

Please submit a full bug report,
with preprocessed source if appropriate.
See <file:///usr/share/doc/gcc-5/README.Bugs> for instructions.
Makefile:46611: recipe for target '.obj/qdrawhelper.o' failed
make[3]: *** [.obj/qdrawhelper.o] Error 1

搜索後，初步斷定是gcc編譯器bug 

Ubuntu 安裝最新的gcc https://gist.github.com/application2000/73fd6f4bf1be6600a2cf9f56315a2d91

These commands are based on a askubuntu answer http://askubuntu.com/a/581497
To install gcc-6 (gcc-6.1.1), I had to do more stuff as shown below.
USE THOSE COMMANDS AT YOUR OWN RISK. I SHALL NOT BE RESPONSIBLE FOR ANYTHING.
ABSOLUTELY NO WARRANTY.

If you are still reading let's carry on with the code.

sudo apt-get update && \
sudo apt-get install build-essential software-properties-common -y && \
sudo add-apt-repository ppa:ubuntu-toolchain-r/test -y && \
sudo apt-get update && \
sudo apt-get install gcc-snapshot -y && \
sudo apt-get update && \
sudo apt-get install gcc-6 g++-6 -y && \
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-6 60 --slave /usr/bin/g++ g++ /usr/bin/g++-6 && \
sudo apt-get install gcc-4.8 g++-4.8 -y && \
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.8 60 --slave /usr/bin/g++ g++ /usr/bin/g++-4.8;

When completed, you must change to the gcc you want to work with by default
sudo update-alternatives --config gcc

To verify if it worked. Just type in your terminal
gcc -v

If everything went fine you should see gcc 6.1.1  by the time I am writing this gist

Happy coding!

gcc升級到6.2.0後編譯經過