build system: make CC/LD derive from HOSTCC/HOSTLD

1. Move HOSTCC/HOSTLD to nmk (note there are rules in nmk
   that make use of these variables already)

2. Make CC/LD derive from HOSTCC/HOSTLD

Note that one can still change anything from the command line.

travis-ci: success for build system: make CC/LD derive from HOSTCC/HOSTLD
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

Makefile

@@ -6,12 +6,6 @@ export __nmk_dir
 include $(__nmk_dir)include.mk
 include $(__nmk_dir)macro.mk
 
-#
-# To build host helpers.
-HOSTCC		?= gcc
-HOSTLD		?= ld
-export HOSTCC HOSTLD
-
 CFLAGS		+= $(USERCFLAGS)
 export CFLAGS
 

scripts/nmk/scripts/tools.mk

@@ -3,8 +3,10 @@ ifndef ____nmk_defined__tools
 #
 # System tools shorthands
 RM		:= rm -f
-LD		:= $(CROSS_COMPILE)ld
-CC		:= $(CROSS_COMPILE)gcc
+HOSTLD		?= ld
+LD		:= $(CROSS_COMPILE)$(HOSTLD)
+HOSTCC		?= gcc
+CC		:= $(CROSS_COMPILE)$(HOSTCC)
 CPP		:= $(CC) -E
 AS		:= $(CROSS_COMPILE)as
 AR		:= $(CROSS_COMPILE)ar
@@ -25,7 +27,7 @@ CSCOPE		:= cscope
 ETAGS		:= etags
 CTAGS		:= ctags
 
-export RM LD CC CPP AS AR STRIP OBJCOPY OBJDUMP
+export RM HOSTLD LD HOSTCC CC CPP AS AR STRIP OBJCOPY OBJDUMP
 export NM SH MAKE MKDIR AWK PERL PYTHON SH CSCOPE
 
 #