Build: Use interface targets for inheriting flags and definitions

* Remove the usage of global flags and definitions
  set through the CMAKE_CXX_FLAGS variable.
* Use cmake target compile features for setting the
  CXX standard automatically.
* Make C++14 globally available in the project
* Closes #21033

(cherry picked from commit e60c1f84a7e13577a82046b02b214f9466d20a7c)

1 files changed, 29 insertions, 10 deletions

diff --git a/cmake/compiler/clang/settings.cmake b/cmake/compiler/clang/settings.cmake
index 1cd95bbf703..204cc6d245a 100644
--- a/cmake/compiler/clang/settings.cmake
+++ b/cmake/compiler/clang/settings.cmake
@@ -1,29 +1,48 @@
 # Set build-directive (used in core to tell which buildtype we used)
-add_definitions(-D_BUILD_DIRECTIVE='"${CMAKE_BUILD_TYPE}"')
+target_compile_definitions(trinity-compile-option-interface
+  INTERFACE
+    -D_BUILD_DIRECTIVE="${CMAKE_BUILD_TYPE}")
 
 if(WITH_WARNINGS)
-  set(WARNING_FLAGS "-W -Wall -Wextra -Winit-self -Wfatal-errors -Wno-mismatched-tags")
-  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${WARNING_FLAGS}")
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${WARNING_FLAGS} -Woverloaded-virtual")
+  target_compile_options(trinity-warning-interface
+    INTERFACE
+      -W
+      -Wall
+      -Wextra
+      -Winit-self
+      -Wfatal-errors
+      -Wno-mismatched-tags
+      -Woverloaded-virtual)
+
   message(STATUS "Clang: All warnings enabled")
 endif()
 
 if(WITH_COREDEBUG)
-  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -g3")
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -g3")
+  target_compile_options(trinity-compile-option-interface
+    INTERFACE
+      -g3)
+
   message(STATUS "Clang: Debug-flags set (-g3)")
 endif()
 
 # -Wno-narrowing needed to suppress a warning in g3d
 # -Wno-deprecated-register is needed to suppress 185 gsoap warnings on Unix systems.
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -Wno-narrowing -Wno-deprecated-register")
-set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -DDEBUG=1")
+target_compile_options(trinity-compile-option-interface
+  INTERFACE
+    -Wno-narrowing
+    -Wno-deprecated-register)
+
+target_compile_definitions(trinity-compile-option-interface
+  INTERFACE
+    -DDEBUG=1)
 
 if (BUILD_SHARED_LIBS)
   # -fPIC is needed to allow static linking in shared libs.
   # -fvisibility=hidden sets the default visibility to hidden to prevent exporting of all symbols.
-  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fPIC -fvisibility=hidden")
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fPIC -fvisibility=hidden")
+  target_compile_options(trinity-compile-option-interface
+    INTERFACE
+      -fPIC
+      -fvisibility=hidden)
 
   # --no-undefined to throw errors when there are undefined symbols
   # (caused through missing TRINITY_*_API macros).