Standardize system include targets

FindBoost-Math.cmake

@@ -4,5 +4,10 @@ endif()
 
 add_library(boost-math INTERFACE)
 
-target_include_directories(boost-math SYSTEM INTERFACE
+if (DEFINED THIRD_PARTY_INCLUDES_AS_SYSTEM AND NOT THIRD_PARTY_INCLUDES_AS_SYSTEM)
+  target_include_directories(boost-math INTERFACE
       ${PROJECT_SOURCE_DIR}/third_party/boost-math/include/)
+else()
+  target_include_directories(boost-math SYSTEM INTERFACE
+      ${PROJECT_SOURCE_DIR}/third_party/boost-math/include/)
+endif()

FindEigen.cmake

@@ -4,16 +4,11 @@ endif()
 
 add_library(eigen INTERFACE)
 
-# Include Eigen library as system headers to suppress warnings when not
-# cross-compiling. GNU ARM toolchain wraps system headers with `extern "C"`,
-# causing errors, so in this case Eigen must be #included using
-# `#pragma GCC system_header` in the source.
-# See https://gcc.gnu.org/onlinedocs/cpp/System-Headers.html
-if (NOT CMAKE_CROSSCOMPILING OR THIRD_PARTY_INCLUDES_AS_SYSTEM)
-  target_include_directories(eigen SYSTEM INTERFACE
+if (DEFINED THIRD_PARTY_INCLUDES_AS_SYSTEM AND NOT THIRD_PARTY_INCLUDES_AS_SYSTEM)
+  target_include_directories(eigen INTERFACE
       ${PROJECT_SOURCE_DIR}/third_party/eigen/)
 else()
-  target_include_directories(eigen INTERFACE
+  target_include_directories(eigen SYSTEM INTERFACE
       ${PROJECT_SOURCE_DIR}/third_party/eigen/)
 endif()
 

FindGFlags.cmake

@@ -1,19 +1,6 @@
 include("GenericFindDependency")
 GenericFindDependency(
-    TARGET gflags
-    SOURCE_DIR "googleflags"
-    )
-
-if(NOT CMAKE_CROSSCOMPILING OR THIRD_PARTY_INCLUDES_AS_SYSTEM)
-  # Change all of GoogleFlags's include directories to be system includes, to avoid
-  # compiler errors. The generalised version of this in GenericFindDependency won't
-  # work here because we are dealing with an aliased target
-  get_target_property(_aliased gflags ALIASED_TARGET)
-  if(_aliased)
-    get_target_property(gflags_include_directories ${_aliased} INTERFACE_INCLUDE_DIRECTORIES)
-    if(gflags_include_directories)
-      set_target_properties(${_aliased} PROPERTIES INTERFACE_INCLUDE_DIRECTORIES "")
-      target_include_directories(${_aliased} SYSTEM INTERFACE ${gflags_include_directories})
-    endif()
-  endif()
-endif()
+  TARGET gflags
+  SOURCE_DIR "googleflags"
+  SYSTEM_INCLUDES
+)

FindGnss-converters.cmake

@@ -4,5 +4,4 @@ GenericFindDependency(
     TARGET gnss_converters
     SOURCE_DIR "gnss-converters/c"
     SYSTEM_HEADER_FILE "gnss-converters/nmea.h"
-    SYSTEM_INCLUDES
     )

FindGoogletest.cmake

@@ -1,7 +1,7 @@
 include("GenericFindDependency")
 GenericFindDependency(
     TARGET gtest
+    ADDITIONAL_TARGETS gmock
     SOURCE_DIR "googletest"
     SYSTEM_INCLUDES
-    )
-mark_target_as_system_includes(gmock)
+)

FindIxcom.cmake

@@ -3,5 +3,4 @@ option(libixcom_ENABLE_TESTS "" OFF)
 GenericFindDependency(
     TARGET ixcom
     SOURCE_DIR "c"
-    SYSTEM_INCLUDES
     )

FindOrion-Proto.cmake

@@ -2,5 +2,4 @@ include("GenericFindDependency")
 GenericFindDependency(
     TARGET orion-proto
     SOURCE_DIR "orion_proto"
-    SYSTEM_INCLUDES
     )

FindPal++.cmake

@@ -3,5 +3,4 @@ option(pal++_ENABLE_TESTS "" OFF)
 GenericFindDependency(
     TARGET pal++
     SOURCE_DIR libpal_cpp
-    SYSTEM_INCLUDES
 )

FindPal.cmake

@@ -3,5 +3,4 @@ option(pal_ENABLE_TESTS "" OFF)
 option(pal_ENABLE_EXAMPLES "" OFF)
 GenericFindDependency(
   TARGET pal
-  SYSTEM_INCLUDES
-  )
+)

FindRapidCheck.cmake

@@ -4,27 +4,9 @@ include("GenericFindDependency")
 set(RC_ENABLE_GTEST ON CACHE BOOL "" FORCE)
 
 GenericFindDependency(
-    TARGET rapidcheck
-    )
-
-# Change all of rapidcheck's include directories to be system includes, to avoid
-# compiler errors. The generalised version in GenericFindDependency isn't suitable
-# in this instance.
-get_target_property(rapidcheck_interface_includes rapidcheck INTERFACE_INCLUDE_DIRECTORIES)
-if(rapidcheck_interface_includes)
-  set_target_properties(rapidcheck PROPERTIES INTERFACE_INCLUDE_DIRECTORIES "")
-  target_include_directories(rapidcheck SYSTEM INTERFACE ${rapidcheck_interface_includes})
-else()
-  message(WARNING "No include directories in rapidcheck, this seems wrong")
-endif()
-unset(rapidcheck_interface_includes)
-
-get_target_property(rapidcheck_gtest_interface_includes rapidcheck_gtest INTERFACE_INCLUDE_DIRECTORIES)
-if(rapidcheck_gtest_interface_includes)
-  set_target_properties(rapidcheck_gtest PROPERTIES INTERFACE_INCLUDE_DIRECTORIES "")
-  target_include_directories(rapidcheck_gtest SYSTEM INTERFACE ${rapidcheck_gtest_interface_includes})
-else()
-  message(WARNING "No include directories in rapidcheck_gtest, this seems wrong")
-endif()
-unset(rapidcheck_gtest_interface_includes)
+  TARGET rapidcheck
+  ADDITIONAL_TARGETS
+    rapidcheck_gtest
+  SYSTEM_INCLUDES
+)
 

FindRtcm.cmake

@@ -4,5 +4,4 @@ GenericFindDependency(
     TARGET rtcm
     SOURCE_DIR "c"
     SYSTEM_HEADER_FILE "rtcm3/bits.h"
-    SYSTEM_INCLUDES
     )

FindSbp.cmake

@@ -4,5 +4,4 @@ option(libsbp_ENABLE_DOCS "" OFF)
 GenericFindDependency(
     TARGET sbp
     SOURCE_DIR "c"
-    SYSTEM_INCLUDES
     )

FindSettings.cmake

@@ -2,5 +2,4 @@ include("GenericFindDependency")
 option(libsettings_ENABLE_TESTS "" OFF)
 GenericFindDependency(
     TARGET settings
-    SYSTEM_INCLUDES
     )

FindStarling.cmake

@@ -1,15 +1,17 @@
 include("GenericFindDependency")
+
 option(starling_ENABLE_TESTS "" OFF)
+option(starling_ENABLE_TEST_LIBS "" OFF)
 option(starling_ENABLE_EXAMPLES "" OFF)
+
 GenericFindDependency(
-    TARGET pvt-runner-lib
-    SOURCE_DIR starling
-    SYSTEM_HEADER_FILE "pvt_driver/runner/pvt_runner.h"
-    SYSTEM_INCLUDES
+  TARGET pvt-runner-lib
+  ADDITIONAL_TARGETS
+    sensorfusion
+    pvt_driver
+    pvt-engine
+    pvt-common
+    starling-util
+  SOURCE_DIR starling
+  SYSTEM_HEADER_FILE "pvt_driver/runner/pvt_runner.h"
 )
-
-mark_target_as_system_includes(sensorfusion)
-mark_target_as_system_includes(pvt_driver)
-mark_target_as_system_includes(pvt-engine)
-mark_target_as_system_includes(pvt-common)
-mark_target_as_system_includes(starling-util)

FindSwiftlets.cmake

@@ -3,5 +3,4 @@ option(swiftlets_ENABLE_TESTS "" OFF)
 GenericFindDependency(
     TARGET swiftlets
     SOURCE_DIR swiftlets
-    SYSTEM_INCLUDES
 )

FindSwiftnav.cmake

@@ -3,5 +3,4 @@ option(libswiftnav_ENABLE_TESTS "" OFF)
 GenericFindDependency(
     TARGET swiftnav
     SYSTEM_HEADER_FILE "swiftnav/bits.h"
-    SYSTEM_INCLUDES
     )

FindUbx.cmake

@@ -3,5 +3,4 @@ option(libubx_ENABLE_TESTS "" OFF)
 GenericFindDependency(
     TARGET ubx
     SOURCE_DIR "c"
-    SYSTEM_INCLUDES
     )

FindVariant.cmake

@@ -1,4 +1,5 @@
 include("GenericFindDependency")
 GenericFindDependency(
     TARGET variant
-    )
+    SYSTEM_INCLUDES
+)

GenericFindDependency.cmake

@@ -21,7 +21,7 @@
 #
 # cmake -DSWIFT_PREFERRED_DEPENDENCY_SOURCE=system <path>
 #
-# will try to use depenedencies from the system libraries rather than bundled
+# will try to use dependencies from the system libraries rather than bundled
 # source code.
 #
 # If the dependency is picked up from the system libraries this function will
@@ -37,12 +37,14 @@
 #
 # The target name can be controlled by the option "TARGET". When using 
 # bundled source code this is used to verify the target was created properly
-# after calling add_subdirectory
+# after calling add_subdirectory. If the add_subdirectory exposes a number of
+# other targets, you can use the "ADDITIONAL_TARGETS" option to list them, this
+# function will apply the "SYSTEM_INCLUDES" option to each of the targets.
 #
 # Passing the option SYSTEM_INCLUDES will rewrite the target include directories
 # so that they are marked as system headers. This will usually be passed to
 # the compiler as an command line option as decided by cmake. Be careful with
-# this option, it will supress warning which might otherwise be helpful.
+# this option, it will suppress warning which might otherwise be helpful.
 #
 # The option REQUIRED can be passed which will cause this function to fail
 # if the dependency was not found for any reason.
@@ -267,12 +269,43 @@ endmacro()
 
 #
 # Helper function to mark the specified target's include directories as system. This is
-# then passed to the compiler which will surpress warnings generated from any header file
+# then passed to the compiler which will suppress warnings generated from any header file
 # included by this path. Use with care
 #
 # Should only be called from GenericFindDependency
 #
 function(mark_target_as_system_includes TGT)
+  #
+  # We will determine if a target is to be set as a system target based on if
+  # THIRD_PARTY_INCLUDES_AS_SYSTEM is explicitly set, otherwise the decision is
+  # delegated to whether or not the SYSTEM_INCLUDES option was specified via
+  # GenericFindDependency. The term "explicitly" is used since in cmake, an
+  # undefined variable is interpreted as false, which is undesirable effect in
+  # this case as we intend to use tri-state property of a variable (undefined/true/false).
+  #
+  if (DEFINED THIRD_PARTY_INCLUDES_AS_SYSTEM)
+    if (THIRD_PARTY_INCLUDES_AS_SYSTEM)
+      set (mark_as_system true)
+    else()
+      set (mark_as_system false)
+    endif()
+  else()
+    if (x_SYSTEM_INCLUDES)
+      set (mark_as_system true)
+    else()
+      set (mark_as_system false)
+    endif()
+  endif()
+
+  if (NOT mark_as_system)
+    return()
+  endif()
+
+  get_target_property(aliased_target ${TGT} ALIASED_TARGET)
+  if (aliased_target)
+    set (TGT ${aliased_target})
+  endif()
+
   get_target_property(directories ${TGT} INTERFACE_INCLUDE_DIRECTORIES)
   if(directories)
     message(STATUS "Marking ${TGT} include directories as system")
@@ -284,7 +317,7 @@ endfunction()
 function(GenericFindDependency)
   set(argOptions "REQUIRED" "SYSTEM_INCLUDES")
   set(argSingleArguments "TARGET" "PREFER" "SOURCE_DIR" "SYSTEM_HEADER_FILE" "SYSTEM_LIB_NAMES")
-  set(argMultiArguments "EXCLUDE")
+  set(argMultiArguments "ADDITIONAL_TARGETS" "EXCLUDE")
 
   cmake_parse_arguments(x "${argOptions}" "${argSingleArguments}" "${argMultiArguments}" ${ARGN})
 
@@ -346,11 +379,7 @@ function(GenericFindDependency)
 
   # Final validation that the target was properly created from some source
   if(TARGET ${x_TARGET})
-    if(x_SYSTEM_INCLUDES)
-      if(NOT CMAKE_CROSSCOMPILING OR THIRD_PARTY_INCLUDES_AS_SYSTEM)
-        mark_target_as_system_includes(${x_TARGET})
-      endif()
-    endif()
+    mark_target_as_system_includes(${x_TARGET})
   else()
     # Target not found in any location
     if(x_REQUIRED OR ${CMAKE_FIND_PACKAGE_NAME}_FIND_REQUIRED)
@@ -359,5 +388,11 @@ function(GenericFindDependency)
       message(WARNING "Could not find dependency ${x_TARGET} in any available location")
     endif()
   endif()
+
+  # If the primary target exposes additional targets, mark them as system
+  # targets in accordance to how the primary target was marked
+  foreach(additional_target IN LISTS x_ADDITIONAL_TARGETS)
+    mark_target_as_system_includes(${additional_target})
+  endforeach()
 endfunction()