[Cin] fileexr build failure with gcc 5.5.0

[Andrew Randrianasulu]

g++ `cat i686/c_flags` -Wno-deprecated -DMSGQUAL=fileexr -c fileexr.C -o i686/fileexr.o
In file included from /usr/include/c++/5.5.0/cstdint:35:0,
                 from /dev/shm/tmp/cinelerra-goodguy-20200320/cinelerra-5.1/cinelerra/../thirdparty/openexr-2.4.1/usr/local/include/OpenEXR/ImfFrameBuffer.h:55,
                 from /dev/shm/tmp/cinelerra-goodguy-20200320/cinelerra-5.1/cinelerra/../thirdparty/openexr-2.4.1/usr/local/include/OpenEXR/ImfInputFile.h:47,
                 from fileexr.C:39:
/usr/include/c++/5.5.0/bits/c++0x_warning.h:32:2: ошибка: #error This file requires compiler and library support for the ISO C++ 2011 standard. This support must be enabled with the -std=c++11 or -std=gnu++11 compiler options.
 #error This file requires compiler and library support \


I put this little " -std=c++11" in CFLAGS not just for decoration..

Porbbaly new-ish gcc will default to this standard, but older ones .....