fix(boost): add compatibility for Boost.Process v1 API in Boost 1.89+

Boost 1.88 replaced Boost.Process with v2, breaking the v1 API.
Boost 1.89 restores v1 compatibility via <boost/process/v1.hpp>.

- Fail configuration if Boost 1.88 is detected
- Define FAIRMQ_BOOST_PROCESS_V1_HEADER for Boost >= 1.89
- Use conditional includes to select v1.hpp or process.hpp
- Add namespace aliases (bp, bp_this) for portable API access

test/CMakeLists.txt

@@ -16,6 +16,10 @@ if(FairLogger_VERSION VERSION_LESS 1.9.0 AND FairLogger_VERSION VERSION_GREATER_
   LIST(APPEND definitions FAIR_MIN_SEVERITY=trace)
 endif()
 
+if(FAIRMQ_BOOST_PROCESS_V1_HEADER)
+  LIST(APPEND definitions FAIRMQ_BOOST_PROCESS_V1_HEADER)
+endif()
+
 if(definitions)
   set(definitions DEFINITIONS ${definitions})
 endif()
@@ -134,6 +138,7 @@ add_testsuite(Device
              ${CMAKE_CURRENT_SOURCE_DIR}/device
              ${CMAKE_CURRENT_BINARY_DIR}
     TIMEOUT 20
+    ${definitions}
     ${environment}
 )
 

test/device/_error_state.cxx

@@ -9,7 +9,11 @@
 #include "runner.h"
 
 #include <gtest/gtest.h>
+#ifdef FAIRMQ_BOOST_PROCESS_V1_HEADER
+#include <boost/process/v1.hpp>
+#else
 #include <boost/process.hpp>
+#endif
 #include <fairmq/tools/Process.h>
 #include <fairmq/tools/Unique.h>
 #include <fairmq/Device.h>

test/device/_exceptions.cxx

@@ -9,7 +9,11 @@
 #include "runner.h"
 
 #include <gtest/gtest.h>
+#ifdef FAIRMQ_BOOST_PROCESS_V1_HEADER
+#include <boost/process/v1.hpp>
+#else
 #include <boost/process.hpp>
+#endif
 #include <fairmq/tools/Process.h>
 #include <fairmq/tools/Unique.h>
 

test/device/_signals.cxx

@@ -9,7 +9,11 @@
 #include "runner.h"
 
 #include <gtest/gtest.h>
+#ifdef FAIRMQ_BOOST_PROCESS_V1_HEADER
+#include <boost/process/v1.hpp>
+#else
 #include <boost/process.hpp>
+#endif
 #include <fairmq/tools/Unique.h>
 #include <fairmq/tools/Process.h>