SUMMARY
I am trying to test the preview scaling, and as such I am trying to compile the git master branch. 

Today's date is 2020-02-06


STEPS TO REPRODUCE
1. Compile kdenlive master branch from git

OBSERVED RESULT
--------------------snip--------------------

[  3%] Building CXX object src/lib/external/media_ctrl/CMakeFiles/media_ctrl.dir/media_ctrl_autogen/mocs_compilation.cpp.o
[  3%] Building C object src/lib/external/media_ctrl/CMakeFiles/media_ctrl.dir/mediactrl.c.o
/data/OS/aur/kdenlive-testing-git/src/kdenlive/src/lib/external/media_ctrl/mediactrl.c: In function 'find_first_device':
/data/OS/aur/kdenlive-testing-git/src/kdenlive/src/lib/external/media_ctrl/mediactrl.c:355:5: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
  355 |     for (int i = 0; i < 32; i++) {
      |     ^~~
/data/OS/aur/kdenlive-testing-git/src/kdenlive/src/lib/external/media_ctrl/mediactrl.c:355:5: note: use option '-std=c99', '-std=gnu99', '-std=c11' or '-std=gnu11' to compile your code
make[2]: *** [src/lib/external/media_ctrl/CMakeFiles/media_ctrl.dir/build.make:76: src/lib/external/media_ctrl/CMakeFiles/media_ctrl.dir/mediactrl.c.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:2267: src/lib/external/media_ctrl/CMakeFiles/media_ctrl.dir/all] Error 2
make: *** [Makefile:130: all] Error 2
==> ERROR: A failure occurred in build().
    Aborting...



EXPECTED RESULT
A clean build. ;)

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 
KDE Frameworks Version: 
Qt Version: 

ADDITIONAL INFORMATION
Arch Linux, last updated 2020-01-14 (ish)