Remove the obsolete comments and change the misleading var name.

Change-Id: Ib19099cbce0133f5c7df44fa0fd80215809a1ad8
diff --git a/core/combo/HOST_darwin-x86.mk b/core/combo/HOST_darwin-x86.mk
index 9459480..28122cd 100644
--- a/core/combo/HOST_darwin-x86.mk
+++ b/core/combo/HOST_darwin-x86.mk
@@ -75,11 +75,11 @@
 endif
 
 HOST_TOOLCHAIN_ROOT := prebuilts/gcc/darwin-x86/host/i686-apple-darwin-4.2.1
-HOST_SDK_TOOLCHAIN_PREFIX := $(HOST_TOOLCHAIN_ROOT)/bin/i686-apple-darwin$(gcc_darwin_version)
+HOST_TOOLCHAIN_PREFIX := $(HOST_TOOLCHAIN_ROOT)/bin/i686-apple-darwin$(gcc_darwin_version)
 # Don't do anything if the toolchain is not there
-ifneq (,$(strip $(wildcard $(HOST_SDK_TOOLCHAIN_PREFIX)-gcc)))
-HOST_CC  := $(HOST_SDK_TOOLCHAIN_PREFIX)-gcc
-HOST_CXX := $(HOST_SDK_TOOLCHAIN_PREFIX)-g++
+ifneq (,$(strip $(wildcard $(HOST_TOOLCHAIN_PREFIX)-gcc)))
+HOST_CC  := $(HOST_TOOLCHAIN_PREFIX)-gcc
+HOST_CXX := $(HOST_TOOLCHAIN_PREFIX)-g++
 ifeq ($(mac_sdk_version),10.8)
 # Mac SDK 10.8 no longer has stdarg.h, etc
 host_toolchain_header := $(HOST_TOOLCHAIN_ROOT)/lib/gcc/i686-apple-darwin$(gcc_darwin_version)/4.2.1/include
@@ -88,7 +88,7 @@
 else
 HOST_CC := gcc
 HOST_CXX := g++
-endif # $(HOST_SDK_TOOLCHAIN_PREFIX)-gcc exists
+endif # $(HOST_TOOLCHAIN_PREFIX)-gcc exists
 HOST_AR := $(AR)
 HOST_STRIP := $(STRIP)
 HOST_STRIP_COMMAND = $(HOST_STRIP) --strip-debug $< -o $@
diff --git a/core/combo/HOST_linux-x86.mk b/core/combo/HOST_linux-x86.mk
index b369199..7ad7e31 100644
--- a/core/combo/HOST_linux-x86.mk
+++ b/core/combo/HOST_linux-x86.mk
@@ -22,23 +22,15 @@
 stat --format "%s" "$(1)" | tr -d '\n'
 endef
 
-# Special case for the Linux SDK: We need to use a special cross-toolchain
-# that generates machine code that will run properly on Ubuntu 8.04 (Hardy)
-# By default, the code generated by the Lucid host toolchain will not run
-# on previous versions of the platform, due to GLibc ABI mistmatches
-# (Lucid is 2.11, Hardy is 2.7)
-#
-# Note that components that need to be built as 64-bit (e.g. clearsilver
-# which is loaded by the 64-bit JVM through JNI), will have to use
-# LOCAL_CC and LOCAL_CXX to override this.
-#
-HOST_SDK_TOOLCHAIN_PREFIX := prebuilts/tools/gcc-sdk
+# Previously the prebiult host toolchain is used only for the sdk build,
+# that's why we have "sdk" in the path name.
+HOST_TOOLCHAIN_PREFIX := prebuilts/tools/gcc-sdk
 # Don't do anything if the toolchain is not there
-ifneq (,$(strip $(wildcard $(HOST_SDK_TOOLCHAIN_PREFIX)/gcc)))
-HOST_CC  := $(HOST_SDK_TOOLCHAIN_PREFIX)/gcc
-HOST_CXX := $(HOST_SDK_TOOLCHAIN_PREFIX)/g++
-HOST_AR  := $(HOST_SDK_TOOLCHAIN_PREFIX)/ar
-endif # $(HOST_SDK_TOOLCHAIN_PREFIX)/gcc exists
+ifneq (,$(strip $(wildcard $(HOST_TOOLCHAIN_PREFIX)/gcc)))
+HOST_CC  := $(HOST_TOOLCHAIN_PREFIX)/gcc
+HOST_CXX := $(HOST_TOOLCHAIN_PREFIX)/g++
+HOST_AR  := $(HOST_TOOLCHAIN_PREFIX)/ar
+endif # $(HOST_TOOLCHAIN_PREFIX)/gcc exists
 
 ifneq ($(strip $(BUILD_HOST_64bit)),)
 # By default we build everything in 32-bit, because it gives us