x86emul: fix test harness and fuzzer build dependencies

Commit fd35f32b4b ("tools/x86emul: Use struct cpuid_policy in the
userspace test harnesses") didn't account for the dependencies of
cpuid-autogen.h to potentially change between incremental builds. In
particular the harness has a "run" goal which is supposed to be usable
independently of the rest of the tools sub-tree building, and both the
harness and the fuzzer code are also supposed to be buildable
independently. Therefore a re-build of the generated header needs to be
triggered first, which is achieved by introducing a new top-level target
pattern (for just the "run" part for now).

Further cpuid.o did not have any dependencies added for it.

Finally, while at it, add a "run" target to the cpu-policy test harness.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>

tools/fuzz/x86_instruction_emulator/Makefile

@@ -26,13 +26,15 @@ GCOV_FLAGS := --coverage
 	$(CC) -c $(CFLAGS) $(GCOV_FLAGS) $< -o $@
 
 x86.h := $(addprefix $(XEN_ROOT)/tools/include/xen/asm/,\
-                     x86-vendors.h x86-defns.h msr-index.h)
+                     x86-vendors.h x86-defns.h msr-index.h) \
+         $(addprefix $(XEN_ROOT)/tools/include/xen/lib/x86/, \
+                     cpuid.h cpuid-autogen.h)
 x86_emulate.h := x86-emulate.h x86_emulate/x86_emulate.h $(x86.h)
 
 # x86-emulate.c will be implicit for both
 x86-emulate.o x86-emulate-cov.o: x86_emulate/x86_emulate.c $(x86_emulate.h)
 
-fuzz-emul.o fuzz-emulate-cov.o wrappers.o: $(x86_emulate.h)
+fuzz-emul.o fuzz-emulate-cov.o cpuid.o wrappers.o: $(x86_emulate.h)
 
 x86-insn-fuzzer.a: fuzz-emul.o x86-emulate.o cpuid.o
 	$(AR) rc $@ $^