Fix typo in definition of `build-art-executable`.

Uses of `LOCAL_MODULES` need two `$` signs within that Make
function definition, so the variable is properly evaluated,
as `build-art-executable` is expanded twice (because it is
used in calls to the `eval` function).

Test: ART_BUILD_HOST_STATIC=true mmma art
Change-Id: I669d493aa7470cb8cde28b2018c784937cd2d335
diff --git a/build/Android.executable.mk b/build/Android.executable.mk
index 2db16af..8576916 100644
--- a/build/Android.executable.mk
+++ b/build/Android.executable.mk
@@ -21,7 +21,7 @@
 
 ART_EXECUTABLES_CFLAGS :=
 
-# $(1): executable ("d" will be appended for debug version)
+# $(1): executable ("d" will be appended for debug version, "s" will be appended for static version)
 # $(2): source
 # $(3): extra shared libraries
 # $(4): extra include directories
@@ -70,7 +70,7 @@
   endif
 
   ifeq ($$(art_static_or_shared),static)
-    LOCAL_MODULE := $(LOCAL_MODULE)s
+    LOCAL_MODULE := $$(LOCAL_MODULE)s
   endif
 
   LOCAL_CFLAGS := $(ART_EXECUTABLES_CFLAGS)