Files missings during build

[mgrallos]

Hi i tried building glew using cmake-testbuild.sh and got these errors

`CMake Error at CMakeLists.txt:209 (add_executable):
Cannot find source file:

/home/asimov-hawks/tello_ws/src/glew/src/glewinfo.c

Tried extensions .c .C .c++ .cc .cpp .cxx .cu .m .M .mm .h .hh .h++ .hm
.hpp .hxx .in .txx

CMake Error at CMakeLists.txt:139 (add_library):
Cannot find source file:

/home/asimov-hawks/tello_ws/src/glew/include/GL/wglew.h

Tried extensions .c .C .c++ .cc .cpp .cxx .cu .m .M .mm .h .hh .h++ .hm
.hpp .hxx .in .txx

CMake Error at CMakeLists.txt:209 (add_executable):
No SOURCES given to target: glewinfo

CMake Error at CMakeLists.txt:139 (add_library):
No SOURCES given to target: glew_s

CMake Error at CMakeLists.txt:135 (add_library):
No SOURCES given to target: glew

CMake Generate step failed. Build files cannot be regenerated correctly.
`

Please let me know if there is another way to build glew. I am using Ubuntu 20.04 ROS Noetic

[nigels-com]

See issue #363

[mgrallos]

See issue #363

Thank you