rawproc: builds with clangs fail on < 10.12

[barracuda156]

[  9%] Building CXX object CMakeFiles/rawproc.dir/src/CurvePane.cpp.o
/opt/local/bin/clang++-mp-16 -DUSE_LIBRTPROCESS -DWXUSINGDLL -D_FILE_OFFSET_BITS=64 -D__WXMAC__ -D__WXOSX_COCOA__ -D__WXOSX__ -I/opt/local/include -I/opt/local/var/macports/build/_opt_bblocal_var_buildworker_ports_build_ports_graphics_rawproc/rawproc/work/rawproc-1.4.0/src/. -I/opt/local/var/macports/build/_opt_bblocal_var_buildworker_ports_build_ports_graphics_rawproc/rawproc/work/rawproc-1.4.0/src/gimage -isystem /opt/local/Library/Frameworks/wxWidgets.framework/Versions/wxWidgets/3.0/lib/wx/include/osx_cocoa-unicode-3.0 -isystem /opt/local/Library/Frameworks/wxWidgets.framework/Versions/wxWidgets/3.0/include/wx-3.0 -pipe -Os -D_LIBCPP_ENABLE_CXX17_REMOVED_FEATURES -Wno-non-pod-varargs -DNDEBUG -isystem/opt/local/include/libcxx/v1 -nostdinc++ -isystem/opt/local/include/LegacySupport -I/opt/local/include -stdlib=libc++ -arch x86_64 -mmacosx-version-min=10.11 -ggdb -DVERSION=\"1.4.0\" -DBUILDDATE=\"2024-06-08T22:11:38\" -fopenmp=libomp -MD -MT CMakeFiles/rawproc.dir/src/CurvePane.cpp.o -MF CMakeFiles/rawproc.dir/src/CurvePane.cpp.o.d -o CMakeFiles/rawproc.dir/src/CurvePane.cpp.o -c /opt/local/var/macports/build/_opt_bblocal_var_buildworker_ports_build_ports_graphics_rawproc/rawproc/work/rawproc-1.4.0/src/CurvePane.cpp
/opt/local/var/macports/build/_opt_bblocal_var_buildworker_ports_build_ports_graphics_rawproc/rawproc/work/rawproc-1.4.0/src/CurvePane.cpp:41:2: error: use of undeclared identifier 'SetDoubleBuffered'
        SetDoubleBuffered(true);
        ^
1 error generated.
make[2]: *** [CMakeFiles/rawproc.dir/src/CurvePane.cpp.o] Error 1
make[2]: *** Waiting for unfinished jobs....

​https://build.macports.org/builders/ports-10.11_x86_64-builder/builds/267878/steps/install-port/logs/stdio

[aeiouaeiouaeiouaeiouaeiouaeiou]

#62087

SetDoubleBuffered is part of the wxWidgets API.