erlang: install to staging

This is required to build custom port drivers/NIFs or code that
uses erl_interface.

Signed-off-by: Hans Bulfone <hans@nil.at>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/erlang/erlang.mk

@@ -12,6 +12,7 @@ HOST_ERLANG_DEPENDENCIES =
 
 ERLANG_LICENSE = EPL
 ERLANG_LICENSE_FILES = EPLICENCE
+ERLANG_INSTALL_STAGING = YES
 
 # The configure checks for these functions fail incorrectly
 ERLANG_CONF_ENV = ac_cv_func_isnan=yes ac_cv_func_isinf=yes