Make -ldl -lrt -lpthread implicit for host builds

Instead of requiring every host module to specify -ldl -lrt -lpthread
and then break the mac build because -lrt doesn't exist, make them
implicit to match the behavior of modules built for the device.

Test: m -j checkbuild
Change-Id: I7b5b5289a41cd8f6e7dc2da59400955d867ee783

core/binary.mk

@@ -290,6 +290,15 @@ my_ldlib_flags :=
 # Move other ldlibs back to shared libraries
 my_shared_libraries += $(patsubst -l%,lib%,$(filter-out $(my_allowed_ldlibs),$(my_ldlibs)))
 my_ldlibs := $(filter $(my_allowed_ldlibs),$(my_ldlibs))
+else # LOCAL_IS_HOST_MODULE
+  # Add -ldl, -lpthread and -lrt to host builds to match the default behavior of
+  # device builds
+  ifneq ($($(my_prefix)OS),windows)
+    my_ldlibs += -ldl -lpthread
+    ifneq ($(HOST_OS),darwin)
+      my_ldlibs += -lrt
+    endif
+  endif
 endif
 
 ifneq ($(LOCAL_SDK_VERSION),)