Fix building static linux binaries

BUILD_HOST_static has been broken because I was stripping
-Wl,--start-group/-Wl,--end-group into a separate set of ldflags instead
of keeping them wrapped around some of the ldlibs. So don't pass some of
the build system flags through the ldlibs checker.

Bug: 30898128
Change-Id: I332b42679695cdc5da3cb0036290b6a3544699c0

core/cxx_stl_setup.mk

@@ -70,6 +70,7 @@ else
     endif
 endif
 
+my_cxx_ldlibs :=
 ifneq ($(filter $(my_cxx_stl),libc++ libc++_static),)
     my_cflags += -D_USING_LIBCXX
 
@@ -89,7 +90,7 @@ ifneq ($(filter $(my_cxx_stl),libc++ libc++_static),)
         my_cppflags += -nostdinc++
         my_ldflags += -nodefaultlibs
         my_ldlibs += -lpthread -lm
-        my_ldlibs += $($($(my_prefix)OS)_$(my_link_type)_gcclibs)
+        my_cxx_ldlibs += $($($(my_prefix)OS)_$(my_link_type)_gcclibs)
     else
         ifeq (arm,$($(my_prefix)$(LOCAL_2ND_ARCH_VAR_PREFIX)ARCH))
             my_static_libraries += libunwind_llvm
@@ -114,7 +115,7 @@ else ifeq ($(my_cxx_stl),none)
     ifdef LOCAL_IS_HOST_MODULE
         my_cppflags += -nostdinc++
         my_ldflags += -nodefaultlibs
-        my_ldlibs += $($($(my_prefix)OS)_$(my_link_type)_gcclibs)
+        my_cxx_ldlibs += $($($(my_prefix)OS)_$(my_link_type)_gcclibs)
     endif
 else
     $(error $(LOCAL_PATH): $(LOCAL_MODULE): $(my_cxx_stl) is not a supported STL.)