Alessandro:
Indeed there is still a problem in cygwin environment (g++ 4.5.3) at the moment of compiling the USER-MISC package. I have found an apparent inconsistency related with the form of declaring the variable "_N" in the initialization of spline function for pair_meam_spline.h and pair_meam_sw_spline.h codes. Maybe someone can explain this??? For now I also solved the problem by deleting these files in src directory before run "make cygwin".
best,
Eric.