kbuild: fix broken builds because of GZIP,BZIP2,LZOP variables

Redefine GZIP, BZIP2, LZOP variables as KGZIP, KBZIP2, KLZOP resp.
GZIP, BZIP2, LZOP env variables are reserved by the tools. The original
attempt to redefine them internally doesn't work in makefiles/scripts
intercall scenarios, e.g., "make GZIP=gzip bindeb-pkg" and results in
broken builds. There can be other broken build commands because of this,
so the universal solution is to use non-reserved env variables for the
compression tools.

Fixes: 8dfb61dcbace ("kbuild: add variables for compression tools")
Signed-off-by: Denis Efremov <efremov@linux.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
diff --git a/arch/m68k/Makefile b/arch/m68k/Makefile
index ce6db5e..0415d28 100644
--- a/arch/m68k/Makefile
+++ b/arch/m68k/Makefile
@@ -135,10 +135,10 @@
 ifndef CONFIG_KGDB
 	cp vmlinux vmlinux.tmp
 	$(STRIP) vmlinux.tmp
-	$(_GZIP) -9c vmlinux.tmp >vmlinux.gz
+	$(KGZIP) -9c vmlinux.tmp >vmlinux.gz
 	rm vmlinux.tmp
 else
-	$(_GZIP) -9c vmlinux >vmlinux.gz
+	$(KGZIP) -9c vmlinux >vmlinux.gz
 endif
 
 bzImage: vmlinux.bz2
@@ -148,10 +148,10 @@
 ifndef CONFIG_KGDB
 	cp vmlinux vmlinux.tmp
 	$(STRIP) vmlinux.tmp
-	$(_BZIP2) -1c vmlinux.tmp >vmlinux.bz2
+	$(KBZIP2) -1c vmlinux.tmp >vmlinux.bz2
 	rm vmlinux.tmp
 else
-	$(_BZIP2) -1c vmlinux >vmlinux.bz2
+	$(KBZIP2) -1c vmlinux >vmlinux.bz2
 endif
 
 archclean: