Without this, users are presented with this endless loop:
$ ffplay
The program ‘ffplay’ is currently not installed. You can install it by
typing:
nix-env -i ffmpeg
$ nix-env -i ffmpeg
$ ffplay
The program ‘ffplay’ is currently not installed. You can install it by
typing:
nix-env -i ffmpeg
Fixes this problem, when building apps in QtCreator:
...(compile output window)
g++ -Wl,-rpath,/nix/store/1w7h7p6s2srfw2ady90k7072991lrnpp-qtbase-5.4.2/lib \
-o qt-test3 main.o mainwindow.o moc_mainwindow.o \
-L/nix/store/1w7h7p6s2srfw2ady90k7072991lrnpp-qtbase-5.4.2/lib \
-lQt5Widgets -lQt5Gui -lQt5Core -lGL -lpthread
/nix/store/b8qhjrwf8sf9ggkjxqqav7f1m6w83bh0-binutils-2.23.1/bin/ld: cannot find -lGL
collect2: error: ld returned 1 exit status
mesa is already in the closure of Qt, so there is no size increase.
The patch is copied into both qt-5.3 and qt-5.4 directories, like other
patches are.
Note that programs still can _run_ against a different libGL (e.g. one
provided by nvidia) by configuring the dynamic linker. For instance,
NixOS sets the LD_LIBRARY_PATH environment variable to
/run/opengl-driver/lib/, meaning that whatever libGL is found there
will be used instead of the default (mesa).
From the changelog:
```
Version 0.7.76, 2015-08-06
+ XML output: line breaks and indents in between attributes for readability
+ Trace feature: XML trace update, only if compiled with trace feature
+ Amazon S3 support (REST API v2), CLI/DLL only and if compiled with
libcurl support
+ FFV1: improved slice analysis (currently activated only with trace
feature and for 1st frame)
x MXF: optimization of the parsing, reading a lot less data (e.g. can be
reduced from 1 GB to 10 MB with some UHD files)
x MXF: wrong frame count with files not having the video stream as the
first stream
x Dolby E in MPEG-TS: "SMPTE ST 302" information was accidentally removed
x MPEG-TS: avoid filling delay from file name, not applicable on MPEG-TS
x MXF: better handling of huge padding blocks, better handling of
descriptors without link to a TrackID
x IMX: streams claiming that they are IMX are actually pure MPEG Video,
probing both IMX and MPEG Video
```
