mpmd: Fix compiler issues

- Initialization of device_addr_t from another using auto doesn't work
  across compilers
- Moved MPMD_DISC_RESPONSE_PREAMBLE to mpmd_find where it belongs

3 files changed, 5 insertions, 7 deletions

diff --git a/host/lib/usrp/mpmd/mpmd_find.cpp b/host/lib/usrp/mpmd/mpmd_find.cpp
index 2f70ec280..a71581e78 100644
--- a/host/lib/usrp/mpmd/mpmd_find.cpp
+++ b/host/lib/usrp/mpmd/mpmd_find.cpp
@@ -16,13 +16,14 @@
 using namespace uhd;
 using namespace uhd::mpmd;
 
-constexpr char mpmd_impl::MPM_DISC_RESPONSE_PREAMBLE[];
-
 namespace {
     //! How long we wait for discovery responses (in seconds)
     constexpr double MPMD_FIND_TIMEOUT = 0.5;
     constexpr char MPMD_CHDR_REACHABILITY_KEY[] = "reachable";
     constexpr char MPMD_CHDR_REACHABILITY_NEGATIVE[] = "No";
+    //! The preamble for any response on the discovery port. Can be used to
+    //  verify that the response is actually an MPM device.
+    constexpr char MPM_DISC_RESPONSE_PREAMBLE[] = "USRP-MPM";
 
     device_addr_t flag_dev_as_unreachable(const device_addr_t& device_args)
     {
@@ -75,7 +76,7 @@ device_addrs_t mpmd_find_with_addr(
         }
         // Verify we didn't receive something other than an MPM discovery
         // response
-        if (result[0] != mpmd_impl::MPM_DISC_RESPONSE_PREAMBLE) {
+        if (result[0] != MPM_DISC_RESPONSE_PREAMBLE) {
             continue;
         }
         const std::string recv_addr = comm->get_recv_addr();
diff --git a/host/lib/usrp/mpmd/mpmd_impl.hpp b/host/lib/usrp/mpmd/mpmd_impl.hpp
index 291ee7fdd..71ad67d65 100644
--- a/host/lib/usrp/mpmd/mpmd_impl.hpp
+++ b/host/lib/usrp/mpmd/mpmd_impl.hpp
@@ -192,9 +192,6 @@ public:
     static const std::string MPM_ECHO_CMD;
     //! This is the RPC command that will return the last known error from MPM.
     static const std::string MPM_RPC_GET_LAST_ERROR_CMD;
-    //! The preamble for any response on the discovery port. Can be used to
-    //  verify that the response is actually an MPM device.
-    static constexpr char MPM_DISC_RESPONSE_PREAMBLE[] = "USRP-MPM";
 
     /**************************************************************************
      * Structors
diff --git a/host/lib/usrp/mpmd/mpmd_mboard_impl.cpp b/host/lib/usrp/mpmd/mpmd_mboard_impl.cpp
index 6df78a9dd..797a3edff 100644
--- a/host/lib/usrp/mpmd/mpmd_mboard_impl.cpp
+++ b/host/lib/usrp/mpmd/mpmd_mboard_impl.cpp
@@ -272,7 +272,7 @@ boost::optional<device_addr_t> mpmd_mboard_impl::is_device_reachable(
             auto chdr_rpcc = uhd::rpc_client::make(chdr_addr, rpc_port);
             chdr_rpcc->set_timeout(MPMD_SHORT_RPC_TIMEOUT);
             chdr_rpcc->request<dev_info>("get_device_info");
-            auto device_addr_copy{device_addr};
+            device_addr_t device_addr_copy = device_addr;
             device_addr_copy["addr"] = chdr_addr;
             return boost::optional<device_addr_t>(device_addr_copy);
         } catch (...) {