diff --git a/tools/build/Build.include b/tools/build/Build.include
index 02489380d79b..1dcb95e76f70 100644
--- a/tools/build/Build.include
+++ b/tools/build/Build.include
@@ -90,6 +90,7 @@ if_changed = $(if $(strip $(any-prereq) $(arg-check)),             \
 # - per object C flags
 # - BUILD_STR macro to allow '-D"$(variable)"' constructs
 c_flags = -Wp,-MD,$(depfile),-MT,$@ $(CFLAGS) -D"BUILD_STR(s)=\#s" $(CFLAGS_$(basetarget).o) $(CFLAGS_$(obj))
+cxx_flags = -Wp,-MD,$(depfile),-MT,$@ $(CXXFLAGS) -D"BUILD_STR(s)=\#s" $(CXXFLAGS_$(basetarget).o) $(CXXFLAGS_$(obj))
 
 ###
 ## HOSTCC C flags
diff --git a/tools/build/Makefile.build b/tools/build/Makefile.build
index 190519a94ce5..99c0ccd2f176 100644
--- a/tools/build/Makefile.build
+++ b/tools/build/Makefile.build
@@ -61,6 +61,9 @@ quiet_cmd_cc_o_c = CC       $@
 quiet_cmd_host_cc_o_c = HOSTCC   $@
       cmd_host_cc_o_c = $(HOSTCC) $(host_c_flags) -c -o $@ $<
 
+quiet_cmd_cxx_o_c = CXX      $@
+      cmd_cxx_o_c = $(CXX) $(cxx_flags) -c -o $@ $<
+
 quiet_cmd_cpp_i_c = CPP      $@
       cmd_cpp_i_c = $(CC) $(c_flags) -E -o $@ $<
 
@@ -88,6 +91,10 @@ $(OUTPUT)%.o: %.c FORCE
 	$(call rule_mkdir)
 	$(call if_changed_dep,$(host)cc_o_c)
 
+$(OUTPUT)%.o: %.cpp FORCE
+	$(call rule_mkdir)
+	$(call if_changed_dep,cxx_o_c)
+
 $(OUTPUT)%.o: %.S FORCE
 	$(call rule_mkdir)
 	$(call if_changed_dep,$(host)cc_o_c)