diff --git a/docs/support-matrix-generate b/docs/support-matrix-generate
index a3d93321f1..8a27849cf6 100755
--- a/docs/support-matrix-generate
+++ b/docs/support-matrix-generate
@@ -27,8 +27,8 @@
 #
 # Then we try to find the next previous revision.  This is done by
 # extracting the current version number from xen/Makefile.  (We make
-# some slight assumption about how xen/Makefile's xenversion target
-# works, because we want to be able to do this without checking out
+# some slight assumption about how xen/Makefile's variables are
+# written, because we want to be able to do this without checking out
 # the whole tree for the version in question.)  Then we use git log on
 # xen/Makefile to try to find a commit where the version changed.
 # This gives us the previous version number, NN.
@@ -102,12 +102,16 @@ commitish_version () {
     esac
 
     git cat-file blob "$commitish:$versionfile" >"$tmp_versionfile"
-    version=$(make --no-print-directory -C docs \
-                   -f "${tmp_versionfile#docs/}" xenversion)
-    case "$version" in
-        *.*.*) version="${version%.*}" ;;
-    esac
-    printf "%s\n" "${version%%-*}"
+
+    local maj=$(sed -n 's/.*XEN_VERSION.*= \([0-9]\+\)/\1/p' < "$tmp_versionfile")
+    local min=$(sed -n 's/.*XEN_SUBVERSION.*= \([0-9]\+\)/\1/p' < "$tmp_versionfile")
+
+    if [ -z $maj ] || [ -z $min ];
+    then
+        fail "Unable to identify Xen version for $commitish";
+    fi
+
+    printf "%d.%d\n" "$maj" "$min"
 }
 
 exec 4>"$tmp_revisions"
diff --git a/xen/Rules.mk b/xen/Rules.mk
index 2e28c57230..ebfd40caff 100644
--- a/xen/Rules.mk
+++ b/xen/Rules.mk
@@ -201,13 +201,13 @@ $(filter %.init.o,$(obj-y) $(obj-bin-y) $(extra-y)): %.init.o: %.o FORCE
 	$(call if_changed,obj_init_o)
 
 quiet_cmd_cpp_i_c = CPP     $@
-cmd_cpp_i_c = $(CPP) $(filter-out -Wa$(comma)%,$(c_flags)) $< -o $@
+cmd_cpp_i_c = $(CPP) $(filter-out -Wa$(comma)%,$(c_flags)) -MQ $@ -o $@ $<
 
 quiet_cmd_cc_s_c = CC      $@
 cmd_cc_s_c = $(CC) $(filter-out -Wa$(comma)%,$(c_flags)) -S $< -o $@
 
 quiet_cmd_s_S = CPP     $@
-cmd_s_S = $(CPP) $(filter-out -Wa$(comma)%,$(a_flags)) $< -o $@
+cmd_s_S = $(CPP) $(filter-out -Wa$(comma)%,$(a_flags)) -MQ $@ -o $@ $<
 
 %.i: %.c FORCE
 	$(call if_changed,cpp_i_c)
diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
index c1a1b5e803..7e82b2178c 100644
--- a/xen/arch/arm/Makefile
+++ b/xen/arch/arm/Makefile
@@ -123,9 +123,7 @@ asm-offsets.s: $(TARGET_SUBARCH)/asm-offsets.c
 	$(CC) $(filter-out -flto,$(c_flags)) -S -o $@ $<
 
 xen.lds: xen.lds.S
-	$(CC) -P -E -Ui386 $(a_flags) -o $@ $<
-	sed -e 's/xen\.lds\.o:/xen\.lds:/g' <.xen.lds.d >.xen.lds.d.new
-	mv -f .xen.lds.d.new .xen.lds.d
+	$(CPP) -P $(a_flags) -MQ $@ -o $@ $<
 
 dtb.o: $(CONFIG_DTB_FILE)
 
diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
index 07eeefbf82..b388861679 100644
--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -244,9 +244,7 @@ $(BASEDIR)/include/asm-x86/asm-macros.h: asm-macros.i Makefile
 
 efi.lds: AFLAGS-y += -DEFI
 xen.lds efi.lds: xen.lds.S
-	$(CC) -P -E -Ui386 $(filter-out -Wa$(comma)%,$(a_flags)) -o $@ $<
-	sed -e 's/.*\.lds\.o:/$(@F):/g' <.$(@F).d >.$(@F).d.new
-	mv -f .$(@F).d.new .$(@F).d
+	$(CPP) -P $(filter-out -Wa$(comma)%,$(a_flags)) -MQ $@ -o $@ $<
 
 boot/mkelf32: boot/mkelf32.c
 	$(HOSTCC) $(HOSTCFLAGS) -o $@ $<