diff --git a/depends/packages/bdb.mk b/depends/packages/bdb.mk
index e507b90a9..50284954c 100644
--- a/depends/packages/bdb.mk
+++ b/depends/packages/bdb.mk
@@ -15,7 +15,7 @@ ifneq ($(build_os),darwin)
 $(package)_config_opts_darwin=--disable-atomicsupport
 endif
 $(package)_config_opts_aarch64=--disable-atomicsupport
-$(package)_cxxflags=-std=c++11
+$(package)_cxxflags+=-std=c++11
 endef
 
 define $(package)_preprocess_cmds
diff --git a/depends/packages/boost.mk b/depends/packages/boost.mk
index 2fe4232f7..530da8447 100644
--- a/depends/packages/boost.mk
+++ b/depends/packages/boost.mk
@@ -21,7 +21,7 @@ $(package)_archiver_$(host_os)=$($(package)_ar)
 $(package)_toolset_darwin=darwin
 $(package)_archiver_darwin=$($(package)_libtool)
 $(package)_config_libraries=chrono,filesystem,program_options,system,thread,test
-$(package)_cxxflags=-std=c++11 -fvisibility=hidden
+$(package)_cxxflags+=-std=c++11 -fvisibility=hidden
 $(package)_cxxflags_linux=-fPIC
 $(package)_cxxflags_freebsd=-fPIC
 endef
diff --git a/depends/packages/zeromq.mk b/depends/packages/zeromq.mk
index e205e9243..546af6789 100644
--- a/depends/packages/zeromq.mk
+++ b/depends/packages/zeromq.mk
@@ -11,7 +11,7 @@ define $(package)_set_vars
   $(package)_config_opts += --disable-drafts --enable-option-checking
   $(package)_config_opts_linux=--with-pic
   $(package)_config_opts_freebsd=--with-pic
-  $(package)_cxxflags=-std=c++11
+  $(package)_cxxflags+=-std=c++11
 endef
 
 define $(package)_config_cmds