https://bugs.gentoo.org/888829

--- a/apps/Makefile
+++ b/apps/Makefile
@@ -41,9 +41,7 @@
 
 include $(SRCDIR)/../Make.defaults
 
-LINUX_HEADERS	= /usr/src/sys/build
 APPSDIR		= $(LIBDIR)/gnuefi/apps
-CPPFLAGS	+= -D__KERNEL__ -I$(LINUX_HEADERS)/include
 CRTOBJS		= $(TOPDIR)/$(ARCH)/gnuefi/crt0-efi-$(ARCH).o
 
 LDSCRIPT	= $(TOPDIR)/gnuefi/elf_$(ARCH)_efi.lds