Merge #16434: build: Specify AM_CPPFLAGS for ZMQ

29ee4c4 Specify AM_CPPFLAGS for ZMQ. (Daniel Kraft)

Pull request description:

  When building the ZMQ static library, add `AM_CPPFLAGS` to the library `CPPFLAGS`.  Otherwise, we may miss important flags that are specified elsewhere.  For instance, if `--enable-debug` is passed and
  `-DDEBUG_LOCKORDER` set, then that would not apply to the ZMQ library before (causing potential for hard-to-find bugs).

ACKs for top commit:
  laanwj:
    utACK 29ee4c4

Tree-SHA512: 64085d71ed3f435a6e4df6dc42bda8b6159a4d292d0547c5b38c09d6ac95e976ad1728cd65278bffdd57363f60a58eb762b1171dafbe055cf94ffcd4f66da877

Author: laanwj

src/Makefile.am

@@ -310,7 +310,7 @@ libbitcoin_server_a_SOURCES += dummywallet.cpp
 endif
 
 if ENABLE_ZMQ
-libbitcoin_zmq_a_CPPFLAGS = $(BITCOIN_INCLUDES) $(ZMQ_CFLAGS)
+libbitcoin_zmq_a_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES) $(ZMQ_CFLAGS)
 libbitcoin_zmq_a_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
 libbitcoin_zmq_a_SOURCES = \
   zmq/zmqabstractnotifier.cpp \