add missing deps

Change-Id: I86a0098b64e02a438c5660ea8b391a9737473aa3

external/boost/StaticLibrary_boostdatetime.mk

@@ -9,6 +9,8 @@
 
 $(eval $(call gb_StaticLibrary_StaticLibrary,boostdatetime))
 
+$(eval $(call gb_StaticLibrary_use_unpacked,boostdatetime,boost))
+
 $(eval $(call gb_StaticLibrary_set_warnings_not_errors,boostdatetime))
 
 # disable "auto link" "feature" on MSVC

external/boost/StaticLibrary_boostsystem.mk

@@ -9,6 +9,8 @@
 
 $(eval $(call gb_StaticLibrary_StaticLibrary,boostsystem))
 
+$(eval $(call gb_StaticLibrary_use_unpacked,boostsystem,boost))
+
 $(eval $(call gb_StaticLibrary_set_warnings_not_errors,boostsystem))
 
 # disable "auto link" "feature" on MSVC

external/boost/StaticLibrary_boostthread.mk

@@ -9,6 +9,8 @@
 
 $(eval $(call gb_StaticLibrary_StaticLibrary,boostthread))
 
+$(eval $(call gb_StaticLibrary_use_unpacked,boostthread,boost))
+
 $(eval $(call gb_StaticLibrary_set_warnings_not_errors,boostthread))
 
 $(eval $(call gb_StaticLibrary_add_defs,boostthread,\