Thanks DJATOM,
Results
Code:
steve@Plex-780:~/AviSynthPlus/avisynth-build$ CC=gcc-9 CXX=g++-9 LD=gcc-9 cmake ../ -G Ninja -DCMAKE_CXX_FLAGS="-fpermissive" && ninja && sudo ninja install
-- Configuring done
-- Generating done
-- Build files have been written to: /home/steve/AviSynthPlus/avisynth-build
[2/66] Building CXX object avs_core/CMakeFiles/AvsCore.dir/core/PluginManager.cpp.o
FAILED: avs_core/CMakeFiles/AvsCore.dir/core/PluginManager.cpp.o
/usr/bin/g++ -DAvsCore_EXPORTS -DBUILDING_AVSCORE -I../avs_core/include -Iavs_core -fpermissive -msse2 -Wl,--no-undefined -fPIC -std=c++1z -MD -MT
avs_core/CMakeFiles/AvsCore.dir/core/PluginManager.cpp.o -MF avs_core/CMakeFiles/AvsCore.dir/core/PluginManager.cpp.o.d
-o avs_core/CMakeFiles/AvsCore.dir/core/PluginManager.cpp.o -c ../avs_core/core/PluginManager.cpp
../avs_core/core/PluginManager.cpp:8:10: fatal error: filesystem: No such file or directory
#include <filesystem>
^~~~~~~~~~~~
compilation terminated.
[7/66] Building CXX object avs_core/CMakeFiles/AvsCore.dir/core/avisynth.cpp.o
../avs_core/core/avisynth.cpp: In member function ‘virtual char* ScriptEnvironment::VSprintf(const char*, void*)’:
../avs_core/core/avisynth.cpp:3142:50: warning: ISO C++ forbids casting to an array type ‘va_list {aka __va_list_tag [1]}’ [-fpermissive]
std::string str = FormatString(fmt, (va_list)val);
^~~
ninja: build stopped: subcommand failed.
steve@Plex-780:~/AviSynthPlus/avisynth-build$
EDIT: Edited a line for line wrap