depends: Enable unicode support on dbd for Windows

Author: ken2812221

depends/packages/bdb.mk

@@ -10,6 +10,7 @@ $(package)_config_opts=--disable-shared --enable-cxx --disable-replication
 $(package)_config_opts_mingw32=--enable-mingw
 $(package)_config_opts_linux=--with-pic
 $(package)_cxxflags=-std=c++11
+$(package)_cppflags_mingw32=-DUNICODE -D_UNICODE
 endef
 
 define $(package)_preprocess_cmds