Workaround build failure on -fno-common toolchains like upstream gcc-10. Otherwise build fails as: ld: AboutDlg.o:/build/pcsxr/gui/Linux.h:42: multiple definition of `cfgfile'; LnxMain.o:/build/pcsxr/gui/Linux.h:42: first defined here
Emulators form a class by themselves. So, they should be moved to applications/.