fwupdate.c: In function 'msleep':
fwupdate.c:54:2: error: 'gBS' undeclared (first use in this function); did you mean 'BS'?
gBS->Stall(msecs);
^~~
BS
fwupdate.c:54:2: note: each undeclared identifier is reported only once for each function it appears in
/build/efi/Makefile:113: recipe for target 'fwupdate.o' failed