diff --git a/depends/packages/bdb.mk b/depends/packages/bdb.mk
index 2370c5b759..262587690c 100644
--- a/depends/packages/bdb.mk
+++ b/depends/packages/bdb.mk
@@ -15,6 +15,9 @@ $(package)_config_opts_netbsd=--with-pic
 $(package)_config_opts_openbsd=--with-pic
 $(package)_config_opts_android=--with-pic
 $(package)_cflags+=-Wno-error=implicit-function-declaration -Wno-error=format-security
+$(package)_cppflags_freebsd=-D_XOPEN_SOURCE=600
+$(package)_cppflags_netbsd=-D_XOPEN_SOURCE=600
+$(package)_cppflags_openbsd=-D_XOPEN_SOURCE=600
 $(package)_cppflags_mingw32=-DUNICODE -D_UNICODE
 endef