diff --git a/Makefile.inc b/Makefile.inc
index 7ce236031e..3840505cd5 100644
--- a/Makefile.inc
+++ b/Makefile.inc
@@ -464,11 +464,24 @@ export $(COREBOOT_EXPORTS)
 
 #######################################################################
 # generate build support files
-$(obj)/build.h: .xcompile
+
+build_h := $(obj)/build.h
+
+# We have to manually export variables that `genbuild_h.sh` uses
+# when we call it through the `$(shell)` function. This is fragile
+# but as variables newly added to `genbuild_h.sh` would just not
+# work, we'd notice that instantly at least.
+build_h_exports := BUILD_TIMELESS KERNELVERSION COREBOOT_EXTRA_VERSION
+
+# Report new `build.ht` as dependency if `build.h` differs.
+build_h_check := \
+	export $(foreach exp,$(build_h_exports),$(exp)="$($(exp))"); \
+	util/genbuild_h/genbuild_h.sh >$(build_h)t 2>/dev/null; \
+	cmp -s $(build_h)t $(build_h) >/dev/null 2>&1 || echo $(build_h)t
+
+$(build_h): $$(shell $$(build_h_check))
 	@printf "    GEN        build.h\n"
-	rm -f $(obj)/build.h
-	util/genbuild_h/genbuild_h.sh > $(obj)/build.ht
-	mv $(obj)/build.ht $(obj)/build.h
+	mv $< $@
 
 build-dirs:
 	mkdir -p $(objcbfs) $(objgenerated)