Centralise the mtools config flag - which makes it impossible to forget to add

Makefile

@@ -88,6 +88,11 @@ list_images:
 # had the same offset to this fat filesystem, so hardcode that offset here.
 FAT_OFFSET := 71680
 
+# Some versions of mtools need this flag set to allow them to work with the
+# dosfs images used by Lenovo - from my tests, it may be that Debian has
+# applied some patch
+export MTOOLS_SKIP_CHECK=1
+
 #
 # Radare didnt seem to let me specify the directory to store the project file,
 # so this target hacks around that
@@ -158,7 +163,7 @@ $(DEPSDIR)/slice.insert.deps: Makefile
 # my mind to it..
 #
 %.iso.bat: %.iso.orig %.iso.orig.desc autoexec.bat.template
-	sed -e "s%__DIR%`MTOOLS_SKIP_CHECK=1 mdir -/ -b -i $<@@$(FAT_OFFSET) |grep FL2 |cut -d/ -f3`%; s%__FL2%`MTOOLS_SKIP_CHECK=1 mdir -/ -b -i $<@@$(FAT_OFFSET) |grep FL2 |cut -d/ -f4`%; s%__DESC%`cat $<.desc`%" autoexec.bat.template >$@.tmp
+	sed -e "s%__DIR%`mdir -/ -b -i $<@@$(FAT_OFFSET) |grep FL2 |cut -d/ -f3`%; s%__FL2%`mdir -/ -b -i $<@@$(FAT_OFFSET) |grep FL2 |cut -d/ -f4`%; s%__DESC%`cat $<.desc`%" autoexec.bat.template >$@.tmp
 	mv $@.tmp $@
 
 # helper to write the ISO onto a cdrw
@@ -181,7 +186,7 @@ $(DEPSDIR)/slice.insert.deps: Makefile
 
 # If we ever want a copy of the dosflash.exe, just get it from the iso image
 %.dosflash.exe.orig: %.iso.orig
-	MTOOLS_SKIP_CHECK=1 mcopy -i $^@@$(FAT_OFFSET) ::FLASH/DOSFLASH.EXE $@
+	mcopy -i $^@@$(FAT_OFFSET) ::FLASH/DOSFLASH.EXE $@
 
 ## Use the system provided geteltorito script, if there is one
 #GETELTORITO := $(shell if type geteltorito >/dev/null; then echo geteltorito; else echo ./geteltorito; fi)
@@ -206,6 +211,7 @@ mec-tools/Makefile:
 	git submodule update --init --remote
 
 mec-tools/mec_encrypt: mec-tools/Makefile
+	git submodule update
 	make -C mec-tools
 
 # using function calls to build rules with actions is kind of a hack,
@@ -220,7 +226,7 @@ endef
 # $1 = FL2 filename
 # $2 = ISO image
 define rule_iso
-    $(2): $(1) $(2).bat ; ./slice.insert $(1).slice $(1) $(2) && MTOOLS_SKIP_CHECK=1 mcopy -o -i $(2)@@$(FAT_OFFSET) $(2).bat ::AUTOEXEC.BAT
+    $(2): $(1) $(2).bat ; ./slice.insert $(1).slice $(1) $(2) && mcopy -o -i $(2)@@$(FAT_OFFSET) $(2).bat ::AUTOEXEC.BAT
 endef
 
 #