kbuild: Use HOST*FLAGS options from the command line

Now that we have the rename in place, reuse the HOST*FLAGS options as
something that can be set from the command line and included with the
rest of the flags.

Signed-off-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/Makefile b/Makefile
index caad81c..433f870 100644
--- a/Makefile
+++ b/Makefile
@@ -360,10 +360,11 @@
 HOSTCC       = gcc
 HOSTCXX      = g++
 KBUILD_HOSTCFLAGS   := -Wall -Wmissing-prototypes -Wstrict-prototypes -O2 \
-		-fomit-frame-pointer -std=gnu89 $(HOST_LFS_CFLAGS)
-KBUILD_HOSTCXXFLAGS := -O2 $(HOST_LFS_CFLAGS)
-KBUILD_HOSTLDFLAGS  := $(HOST_LFS_LDFLAGS)
-KBUILD_HOSTLDLIBS   := $(HOST_LFS_LIBS)
+		-fomit-frame-pointer -std=gnu89 $(HOST_LFS_CFLAGS) \
+		$(HOSTCFLAGS)
+KBUILD_HOSTCXXFLAGS := -O2 $(HOST_LFS_CFLAGS) $(HOSTCXXFLAGS)
+KBUILD_HOSTLDFLAGS  := $(HOST_LFS_LDFLAGS) $(HOSTLDFLAGS)
+KBUILD_HOSTLDLIBS   := $(HOST_LFS_LIBS) $(HOSTLDLIBS)
 
 # Make variables (CC, etc...)
 AS		= $(CROSS_COMPILE)as