Yes, you can. There are a few things to keep in mind when doing so.

• The mere use of gcc to compile your program, or the use of libc.a/libm.a to link your program, does not change the copyright status of your application.

• If you use any source code protected by the GPL in your application, your entire application becomes GPL. This may happen if you use a routine from gcc's sources, or if you use bison, which inserts GPL source code into its output.

• If you use libgpp.a, and you do not use gcc to compile your application, the LGPL applies to libgpp.a. If you use gcc, you don't have to worry.

• You may ship anything in the Execution Only Environment (djeoe*.zip) as distributed by me with no other requirement besides telling your customers how to get djgpp for themselves.