Look for a fxe, gxp or elf file. If that doesnt work you may want to look at the dos box that pops up, is it erroring somewhere? If the compiler errors on your code, then of course there will not be an output file. Try compiling this file using a dos prompt and not the IDE. The devkitadv compiler doesnt like things // comments, so make sure your code is nice and properly formated for Mingw/GCC
More than likely its outputting the compiled files (elf, o, etc..) properly, but the next stage may not be working (to fxe) and then, as its told to do, it cleans up all of the (elf, o, gxb, etc...) files. Making it look like there was no output. watch the Dos Box for errors, try using a dos prompt to manually compile and see if you get the same results.
Also make sure your "make" file has the proper file names and source name, otherwise it will not find the objects / primary source code file.