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

1 files changed, 25 insertions, 10 deletions

diff --git a/cmake/compiler/mingw/settings.cmake b/cmake/compiler/mingw/settings.cmake
index 68156bd0b6b..e3c75581648 100644
--- a/cmake/compiler/mingw/settings.cmake
+++ b/cmake/compiler/mingw/settings.cmake
@@ -2,26 +2,41 @@
 set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
 
 # 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(PLATFORM EQUAL 32)
   # Required on 32-bit systems to enable SSE2 (standard on x64)
-  set(SSE_FLAGS "-msse2 -mfpmath=sse")
-  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${SSE_FLAGS}")
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${SSE_FLAGS}")
+  target_compile_options(trinity-compile-option-interface
+    INTERFACE
+      -msse2
+      -mfpmath=sse)
 endif()
-add_definitions(-DHAVE_SSE2 -D__SSE2__)
+target_compile_definitions(trinity-compile-option-interface
+  INTERFACE
+    -DHAVE_SSE2
+    -D__SSE2__)
 message(STATUS "GCC: SFMT enabled, SSE2 flags forced")
 
 if( WITH_WARNINGS )
-  set(WARNING_FLAGS "-W -Wall -Wextra -Winit-self -Winvalid-pch -Wfatal-errors")
-  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
+      -Winvalid-pch
+      -Wfatal-errors
+      -Woverloaded-virtual)
+
   message(STATUS "GCC: 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 "GCC: Debug-flags set (-g3)")
 endif()