Compile freeglut error in GCC 10.1.0

[ElonKou]

OS : ubuntu 20.04
GCC : GCC 10.1.0

Thanks for your great work , I am an engineer and I found that freeglut can't be compiled in GCC 10.1.0 when I run the command './build.sh", but GCC 9.4.0 runs well.

error info:

[ 31%] Building C object CMakeFiles/Lorenz_static.dir/progs/demos/Lorenz/lorenz.c.o
[ 32%] Linking C executable bin/Lorenz_static
/usr/bin/ld: lib/libglut.a(fg_gl2.c.o):(.bss+0x0): multiple definition of `fghGenBuffers'; lib/libglut.a(fg_window.c.o):(.bss+0x0): first defined here
/usr/bin/ld: lib/libglut.a(fg_gl2.c.o):(.bss+0x8): multiple definition of `fghDeleteBuffers'; lib/libglut.a(fg_window.c.o):(.bss+0x8): first defined here