v0.21.0 fails to compile due to missing header

[ThePyrotechnic]

When compiling v0.21.0 on an up-to-date x86 Arch Linux PC, I receive the following error:
(I have also observed this on the master branch as of 919f06e)

[ 50%] Building CXX object CMakeFiles/datachannel.dir/src/nalunit.cpp.o
<truncated>/libdatachannel/src/h264rtpdepacketizer.cpp: In member function ‘virtual void rtc::H264RtpDepacketizer::incoming(rtc::message_vector&, const rtc::message_callback&)’:
<truncated>/libdatachannel/src/h264rtpdepacketizer.cpp:116:29: error: ‘remove_if’ is not a member of ‘std’; did you mean ‘remove_cv’?
  116 |         messages.erase(std::remove_if(messages.begin(), messages.end(),
      |                             ^~~~~~~~~
      |                             remove_cv
make[2]: *** [CMakeFiles/datachannel.dir/build.make:328: CMakeFiles/datachannel.dir/src/h264rtpdepacketizer.cpp.o] Error 1
make[2]: *** Waiting for unfinished jobs....
make[1]: *** [CMakeFiles/Makefile2:355: CMakeFiles/datachannel.dir/all] Error 2
make: *** [Makefile:136: all] Error 2

From cppreference it seems that remove_if requires the <algorithm> header to be imported
I've attached the following patch that I used to test (below), but I'm not sure if this is the best place for the include since I am not familiar with the project.
0001-Include-algorithm-to-use-std-remove_if.patch.txt

[paullouisageneau]

Thank you for reporting, this is fixed in #1176. Your patch is fine but I prefer headers needed only by the implementation to be imported in the .cpp file.