Lunch: don't use a toolchain that doesn't exist.

"lunch sdk-eng" on cygwin tries to use a gcc.exe from the
prebuild arm toolchain, but it doesn't exist. This prevents
from setting variables to point on a gcc toolchain if there
is none for the given arch.

Change-Id: I3b72220663687f9fdaacc050899aef00632f2c3c
diff --git a/core/combo/TARGET_linux-arm.mk b/core/combo/TARGET_linux-arm.mk
index f7a1756..67844c8 100644
--- a/core/combo/TARGET_linux-arm.mk
+++ b/core/combo/TARGET_linux-arm.mk
@@ -47,13 +47,17 @@
 	prebuilt/$(HOST_PREBUILT_TAG)/toolchain/arm-eabi-4.4.3/bin/arm-eabi-
 endif
 
-TARGET_CC := $(TARGET_TOOLS_PREFIX)gcc$(HOST_EXECUTABLE_SUFFIX)
-TARGET_CXX := $(TARGET_TOOLS_PREFIX)g++$(HOST_EXECUTABLE_SUFFIX)
-TARGET_AR := $(TARGET_TOOLS_PREFIX)ar$(HOST_EXECUTABLE_SUFFIX)
-TARGET_OBJCOPY := $(TARGET_TOOLS_PREFIX)objcopy$(HOST_EXECUTABLE_SUFFIX)
-TARGET_LD := $(TARGET_TOOLS_PREFIX)ld$(HOST_EXECUTABLE_SUFFIX)
-TARGET_STRIP := $(HOST_OUT_EXECUTABLES)/soslim$(HOST_EXECUTABLE_SUFFIX)
-TARGET_STRIP_COMMAND = $(TARGET_STRIP) --strip --shady --quiet $< --outfile $@
+# Only define these if there's actually a gcc in there.
+# The gcc toolchain does not exists for windows/cygwin. In this case, do not reference it.
+ifneq ($(wildcard $(TARGET_TOOLS_PREFIX)gcc$(HOST_EXECUTABLE_SUFFIX)),)
+    TARGET_CC := $(TARGET_TOOLS_PREFIX)gcc$(HOST_EXECUTABLE_SUFFIX)
+    TARGET_CXX := $(TARGET_TOOLS_PREFIX)g++$(HOST_EXECUTABLE_SUFFIX)
+    TARGET_AR := $(TARGET_TOOLS_PREFIX)ar$(HOST_EXECUTABLE_SUFFIX)
+    TARGET_OBJCOPY := $(TARGET_TOOLS_PREFIX)objcopy$(HOST_EXECUTABLE_SUFFIX)
+    TARGET_LD := $(TARGET_TOOLS_PREFIX)ld$(HOST_EXECUTABLE_SUFFIX)
+    TARGET_STRIP := $(HOST_OUT_EXECUTABLES)/soslim$(HOST_EXECUTABLE_SUFFIX)
+    TARGET_STRIP_COMMAND = $(TARGET_STRIP) --strip --shady --quiet $< --outfile $@
+endif
 
 TARGET_NO_UNDEFINED_LDFLAGS := -Wl,--no-undefined
 
diff --git a/core/dumpvar.mk b/core/dumpvar.mk
index 0c58559..58cdc6d 100644
--- a/core/dumpvar.mk
+++ b/core/dumpvar.mk
@@ -8,8 +8,11 @@
 ifeq ($(TARGET_SIMULATOR),true)
 	ABP:=$(ABP):$(TARGET_OUT_EXECUTABLES)
 else
-	# this should be copied to HOST_OUT_EXECUTABLES instead
-	ABP:=$(ABP):$(PWD)/prebuilt/$(HOST_PREBUILT_TAG)/toolchain/arm-eabi-4.4.3/bin
+	# Add the toolchain bin dir if it actually exists
+	ifneq ($(wildcard $(PWD)/prebuilt/$(HOST_PREBUILT_TAG)/toolchain/arm-eabi-4.4.3/bin),)
+		# this should be copied to HOST_OUT_EXECUTABLES instead
+		ABP:=$(ABP):$(PWD)/prebuilt/$(HOST_PREBUILT_TAG)/toolchain/arm-eabi-4.4.3/bin
+	endif
 endif
 ANDROID_BUILD_PATHS := $(ABP)
 ANDROID_PREBUILTS := prebuilt/$(HOST_PREBUILT_TAG)