x86, um: Use the same style generated syscall tables as native

Now when the native kernel uses a single style of generated system
call table, follow suite for UML and implement the same style, all in
C.  This requires __NR_syscall_max and NR_syscalls to be generated; on
native this is done in asm-headers.h but that file is common to all
UML architectures; therefore put it in user-headers.h instead which
already have accommodations for architecture-specific values.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
diff --git a/arch/x86/um/Makefile b/arch/x86/um/Makefile
index 8fb5840..5d065b2 100644
--- a/arch/x86/um/Makefile
+++ b/arch/x86/um/Makefile
@@ -37,7 +37,8 @@
 USER_OBJS := bugs_$(BITS).o ptrace_user.o fault.o
 
 extra-y += user-offsets.s
-$(obj)/user-offsets.s: c_flags = -Wp,-MD,$(depfile) $(USER_CFLAGS)
+$(obj)/user-offsets.s: c_flags = -Wp,-MD,$(depfile) $(USER_CFLAGS) \
+	-Iarch/x86/include/generated
 
 UNPROFILE_OBJS := stub_segv.o
 CFLAGS_stub_segv.o := $(CFLAGS_NO_HARDENING)