Enable sendfile, used by other modules

Signed-off-by: Cyril Soldani <cyril.soldani@uliege.be>
Tested-by: Unikraft CI <monkey@unikraft.io>
GitHub-Pull-Request: unikraft#3

Author: cffs

Makefile.uk.musl.linux

@@ -24,7 +24,7 @@ LIBMUSL_LINUX_HDRS-y += $(LIBMUSL)/include/sys/ptrace.h
 LIBMUSL_LINUX_HDRS-y += $(LIBMUSL)/include/sys/quota.h
 LIBMUSL_LINUX_HDRS-y += $(LIBMUSL)/include/sys/reboot.h
 LIBMUSL_LINUX_HDRS-y += $(LIBMUSL)/include/sys/resource.h
-#LIBMUSL_LINUX_HDRS-y += $(LIBMUSL)/include/sys/sendfile.h
+LIBMUSL_LINUX_HDRS-y += $(LIBMUSL)/include/sys/sendfile.h
 LIBMUSL_LINUX_HDRS-y += $(LIBMUSL)/include/sys/signalfd.h
 LIBMUSL_LINUX_HDRS-y += $(LIBMUSL)/include/sys/swap.h
 LIBMUSL_LINUX_HDRS-y += $(LIBMUSL)/include/sys/sysinfo.h