Fix protobuf backend build dependencies

backends/protobuf/protobuf.cc depends on the source and header files
generated by protoc, but this dependency wasn't explicitly declared. Add
a rule to the Makefile to fix intermittent build failures when the
protobuf header/source file isn't built before protobuf.cc.

diff --git a/backends/protobuf/Makefile.inc b/backends/protobuf/Makefile.inc
index 834cad42cde903ed6cfd05353e566e8b2368cc03..9cac9dcaa2e054ef20cb225f182711a695dcf865 100644 (file)
--- a/backends/protobuf/Makefile.inc
+++ b/backends/protobuf/Makefile.inc
@@ -3,6 +3,8 @@ ifeq ($(ENABLE_PROTOBUF),1)
 backends/protobuf/yosys.pb.cc backends/protobuf/yosys.pb.h: misc/yosys.proto
        $(Q) cd misc && protoc --cpp_out "../backends/protobuf" yosys.proto
 
+backends/protobuf/protobuf.cc: backends/protobuf/yosys.pb.h
+
 OBJS += backends/protobuf/protobuf.o backends/protobuf/yosys.pb.o
 
 endif