build: Add NS3_FORCE_LOCAL_DEPENDENCIES option to ignore system directories

CMakeLists.txt

@@ -60,6 +60,11 @@ option(NS3_FAST_LINKERS "Use Mold or LLD to speed up linking if available" ON)
 option(NS3_FETCH_OPTIONAL_COMPONENTS
        "Fetch Brite, Click and Openflow dependencies" OFF
 )
+option(
+  NS3_FORCE_LOCAL_DEPENDENCIES
+  "Only search applications, headers, libraries on explicitly set directories"
+  OFF
+)
 option(NS3_GSL "Build with GSL support" ON)
 option(NS3_GTK3 "Build with GTK3 support" ON)
 option(NS3_LINK_TIME_OPTIMIZATION "Build with link-time optimization" OFF)

build-support/3rd-party/find-program-hints.cmake

@@ -1,4 +1,5 @@
 disable_cmake_warnings()
+string(REPLACE ";" "/bin;" syspaths "${CMAKE_SYSTEM_PREFIX_PATH};")
 set(3RD_PARTY_FIND_PROGRAM_HINTS
     # find_program HINTS for Doxygen
     # https://gitlab.kitware.com/cmake/cmake/-/blob/master/Modules/FindDoxygen.cmake
@@ -18,5 +19,6 @@ set(3RD_PARTY_FIND_PROGRAM_HINTS
     "[HKEY_LOCAL_MACHINE\\SOFTWARE\\ATT\\Graphviz;InstallPath]/bin"
     /Applications/Graphviz.app/Contents/MacOS
     /Applications/Utilities/Graphviz.app/Contents/MacOS
+    ${syspaths}
 )
 enable_cmake_warnings()

build-support/custom-modules/ns3-find-external-library.cmake

@@ -111,6 +111,9 @@ function(find_external_library)
       # directories
       $ENV{PATH} # Search for libraries in PATH directories
   )
+  if(library_search_paths)
+    list(REMOVE_DUPLICATES library_search_paths)
+  endif()
   enable_cmake_warnings()
   # cmake-format: off
     #
@@ -223,6 +226,9 @@ function(find_external_library)
       # ns-3-dev/build
       ${CMAKE_INSTALL_PREFIX} # Search for headers in the install
   )
+  if(header_search_paths)
+    list(REMOVE_DUPLICATES header_search_paths)
+  endif()
 
   set(not_found_headers)
   set(include_dirs)

build-support/macros-and-definitions.cmake

@@ -221,6 +221,13 @@ macro(process_options)
     unset(CMAKE_VERBOSE_MAKEFILE CACHE)
   endif()
 
+  if(${NS3_FORCE_LOCAL_DEPENDENCIES})
+    set(CMAKE_FIND_FRAMEWORK NEVER)
+    set(CMAKE_FIND_APPBUNDLE NEVER)
+    set(CMAKE_FIND_USE_CMAKE_SYSTEM_PATH FALSE)
+    set(CMAKE_FIND_USE_SYSTEM_ENVIRONMENT_PATH FALSE)
+  endif()
+
   # Set warning level and warning as errors
   if(${NS3_WARNINGS})
     if(DEFINED MSVC)