lib: Fix compiler warnings with GCC 16 / Python 3.14

sim_find.cpp: Python 3.14's pyconfig.h redefines _POSIX_C_SOURCE and
_XOPEN_SOURCE to older values, but only if they haven't been defined yet.
Moving <Python.h> to be the first include (before any system header that
pulls in features.h via <string>) prevents the -Wmacro-redefinition
warnings that become errors under -Werror.

usrprio_rpc_client.cpp: Value-initialize usrprio_device_info to silence
-Wmaybe-uninitialized on the interface_num member, caught by GCC 16.

host/lib/transport/nirio/rpc/usrprio_rpc_client.cpp

@@ -53,7 +53,7 @@ nirio_status usrprio_rpc_client::niusrprio_enumerate(NIUSRPRIO_ENUMERATE_ARGS)
     if (nirio_status_not_fatal(status) && vtr_size > 0) {
         device_info_vtr.resize(vtr_size);
         for (size_t i = 0; i < (size_t)vtr_size; i++) {
-            usrprio_device_info info;
+            usrprio_device_info info{};
             try {
                 out_args >> info;
             } catch (std::exception&) {

host/lib/usrp/mpmd/sim_find.cpp

@@ -4,13 +4,17 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
 //
 
+// Python.h must be included before any system header that pulls in features.h,
+// otherwise Python 3.14+ pyconfig.h will attempt to redefine _POSIX_C_SOURCE
+// and _XOPEN_SOURCE after glibc has already set them to newer values.
+// Need this import because pybind11 doesn't have an equivalent to Py_IsInitialized()
+#include <Python.h>
+
 #include "mpmd_devices.hpp"
 #include "mpmd_impl.hpp"
 #include <uhd/device.hpp>
 #include <uhd/utils/static.hpp>
 #include <uhdlib/rfnoc/rfnoc_device.hpp>
-// Need this import because pybind doesn't have an equivalent to Py_IsInitialized()
-#include <Python.h>
 #include <pybind11/embed.h>
 #include <pybind11/pybind11.h>
 #include <chrono>