link run_pbwo4 to build root in both build modes

Superbuild: install step creates build/run_pbwo4 symlink pointing at
the executable in build/minicalosim-build/.
Regular build: CMAKE_RUNTIME_OUTPUT_DIRECTORY ensures the executable
lands in build/ regardless of generator.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

CMakeLists.txt

@@ -55,6 +55,8 @@ target_link_libraries(minicalo PUBLIC ${Geant4_LIBRARIES} ${Python3_LIBRARIES})
 #----------------------------------------------------------------------------
 # Add the executable, and link it to the Geant4 and Python libraries
 #
+set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR})
+
 add_executable(run_pbwo4 run_pbwo4.cc ${sources} ${headers})
 target_link_libraries(run_pbwo4 ${Geant4_LIBRARIES} ${Python3_LIBRARIES})
 

superbuild/CMakeLists.txt

@@ -43,6 +43,8 @@ ExternalProject_Add(run_pbwo4
     -DCMAKE_PREFIX_PATH=${G4_INSTALL}
     -DWITH_GEANT4_UIVIS=OFF
   BUILD_COMMAND   cmake --build <BINARY_DIR> --target run_pbwo4 --parallel ${NPROC}
-  INSTALL_COMMAND ""
+  INSTALL_COMMAND ${CMAKE_COMMAND} -E create_symlink
+    ${CMAKE_BINARY_DIR}/minicalosim-build/run_pbwo4
+    ${CMAKE_BINARY_DIR}/run_pbwo4
   DEPENDS geant4
 )