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)

5 files changed, 169 insertions, 59 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).
diff --git a/cmake/compiler/gcc/settings.cmake b/cmake/compiler/gcc/settings.cmake
index b9d2e457df8..d854ff521ce 100644
--- a/cmake/compiler/gcc/settings.cmake
+++ b/cmake/compiler/gcc/settings.cmake
@@ -1,5 +1,7 @@
 # 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}")
 
 set(GCC_EXPECTED_VERSION 6.3.0)
 
@@ -7,37 +9,47 @@ if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS GCC_EXPECTED_VERSION)
   message(FATAL_ERROR "GCC: TrinityCore requires version ${GCC_EXPECTED_VERSION} to build but found ${CMAKE_CXX_COMPILER_VERSION}")
 endif()
 
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
-message(STATUS "GCC: Enabled c++11 support")
-
-set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=gnu99")
-message(STATUS "GCC: Enabled C99 support")
-
 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()
 
 if (BUILD_SHARED_LIBS)
-  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fPIC -fvisibility=hidden -Wno-attributes")
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fPIC -fvisibility=hidden -Wno-attributes")
+  target_compile_options(trinity-compile-option-interface
+    INTERFACE
+      -fPIC
+      -fvisibility=hidden
+      -Wno-attributes)
 
   # Should break the build when there are TRINITY_*_API macros missing
   # but it complains about missing references in precompiled headers.
diff --git a/cmake/compiler/icc/settings.cmake b/cmake/compiler/icc/settings.cmake
index 133bc15e59e..563b92d6b9b 100644
--- a/cmake/compiler/icc/settings.cmake
+++ b/cmake/compiler/icc/settings.cmake
@@ -1,18 +1,28 @@
-# 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)
-  add_definitions(-axSSE2)
+  target_compile_options(trinity-compile-option-interface
+    INTERFACE
+      -axSSE2)
 else()
-  add_definitions(-xSSE2)
+  target_compile_options(trinity-compile-option-interface
+    INTERFACE
+      -xSSE2)
 endif()
 
 if( WITH_WARNINGS )
-  add_definitions(-w1)
+  target_compile_options(trinity-warning-interface
+    INTERFACE
+      -w1)
+
   message(STATUS "ICC: All warnings enabled")
 endif()
 
 if( WITH_COREDEBUG )
-  add_definitions(-g)
+  target_compile_options(trinity-compile-option-interface
+    INTERFACE
+      -g)
   message(STATUS "ICC: Debug-flag set (-g)")
 endif()
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()
diff --git a/cmake/compiler/msvc/settings.cmake b/cmake/compiler/msvc/settings.cmake
index fb5232a66f6..58e3eb79d4d 100644
--- a/cmake/compiler/msvc/settings.cmake
+++ b/cmake/compiler/msvc/settings.cmake
@@ -7,6 +7,19 @@ if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS MSVC_EXPECTED_VERSION)
   message(FATAL_ERROR "MSVC: TrinityCore requires version ${MSVC_EXPECTED_VERSION} (MSVC 2015 Update 3) to build but found ${CMAKE_CXX_COMPILER_VERSION}")
 endif()
 
+# CMake sets warning flags by default, however we manage it manually
+# for different core and dependency targets
+string(REGEX REPLACE "/W[0-4] " "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
+# Search twice, once for space after /W argument,
+# once for end of line as CMake regex has no \b
+string(REGEX REPLACE "/W[0-4]$" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
+string(REGEX REPLACE "/W[0-4] " "" CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")
+string(REGEX REPLACE "/W[0-4]$" "" CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")
+
+target_compile_options(trinity-warning-interface
+  INTERFACE
+    /W3)
+
 # set up output paths ofr static libraries etc (commented out - shown here as an example only)
 #set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
 #set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
@@ -15,7 +28,10 @@ if(PLATFORM EQUAL 64)
   # This definition is necessary to work around a bug with Intellisense described
   # here: http://tinyurl.com/2cb428.  Syntax highlighting is important for proper
   # debugger functionality.
-  add_definitions("-D_WIN64")
+  target_compile_definitions(trinity-compile-option-interface
+    INTERFACE
+      -D_WIN64)
+
   message(STATUS "MSVC: 64-bit platform, enforced -D_WIN64 parameter")
 
 else()
@@ -23,7 +39,9 @@ else()
   set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} /LARGEADDRESSAWARE")
   message(STATUS "MSVC: Enabled large address awareness")
 
-  add_definitions(/arch:SSE2)
+  target_compile_options(trinity-compile-option-interface
+    INTERFACE
+      /arch:SSE2)
   message(STATUS "MSVC: Enabled SSE2 support")
 
   set(CMAKE_EXE_LINKER_FLAGS_DEBUG "${CMAKE_EXE_LINKER_FLAGS_DEBUG} /SAFESEH:NO")
@@ -33,18 +51,27 @@ endif()
 # Set build-directive (used in core to tell which buildtype we used)
 # msbuild/devenv don't set CMAKE_MAKE_PROGRAM, you can choose build type from a dropdown after generating projects
 if("${CMAKE_MAKE_PROGRAM}" MATCHES "MSBuild")
-  add_definitions(-D_BUILD_DIRECTIVE=\\"$(ConfigurationName)\\")
+  target_compile_definitions(trinity-compile-option-interface
+    INTERFACE
+      -D_BUILD_DIRECTIVE="$(ConfigurationName)")
 else()
   # while all make-like generators do (nmake, ninja)
-  add_definitions(-D_BUILD_DIRECTIVE=\\"${CMAKE_BUILD_TYPE}\\")
+  target_compile_definitions(trinity-compile-option-interface
+    INTERFACE
+      -D_BUILD_DIRECTIVE="${CMAKE_BUILD_TYPE}")
 endif()
 
 # multithreaded compiling on VS
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /MP")
+target_compile_options(trinity-compile-option-interface
+  INTERFACE
+    /MP)
 
 if((PLATFORM EQUAL 64) OR (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 19.0.23026.0) OR BUILD_SHARED_LIBS)
   # Enable extended object support
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /bigobj")
+  target_compile_options(trinity-compile-option-interface
+    INTERFACE
+      /bigobj)
+
   message(STATUS "MSVC: Enabled increased number of sections in object files")
 endif()
 
@@ -55,36 +82,60 @@ endif()
 # http://blogs.msdn.com/b/vcblog/archive/2015/08/06/new-in-vs-2015-zc-throwingnew.aspx
 if(NOT (CMAKE_CXX_COMPILER_VERSION VERSION_LESS 19.0.23026.0))
   # makes this flag a requirement to build TC at all
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /Zc:throwingNew")
+  target_compile_options(trinity-compile-option-interface
+    INTERFACE
+      /Zc:throwingNew)
 endif()
 
 # Define _CRT_SECURE_CPP_OVERLOAD_STANDARD_NAMES - eliminates the warning by changing the strcpy call to strcpy_s, which prevents buffer overruns
-add_definitions(-D_CRT_SECURE_CPP_OVERLOAD_STANDARD_NAMES)
+target_compile_definitions(trinity-compile-option-interface
+  INTERFACE
+    -D_CRT_SECURE_CPP_OVERLOAD_STANDARD_NAMES)
 message(STATUS "MSVC: Overloaded standard names")
 
 # Ignore warnings about older, less secure functions
-add_definitions(-D_CRT_SECURE_NO_WARNINGS)
+target_compile_definitions(trinity-compile-option-interface
+  INTERFACE
+    -D_CRT_SECURE_NO_WARNINGS)
 message(STATUS "MSVC: Disabled NON-SECURE warnings")
 
 # Ignore warnings about POSIX deprecation
-add_definitions(-D_CRT_NONSTDC_NO_WARNINGS)
+target_compile_definitions(trinity-compile-option-interface
+  INTERFACE
+    -D_CRT_NONSTDC_NO_WARNINGS)
+
 message(STATUS "MSVC: Disabled POSIX warnings")
 
 # Ignore specific warnings
 # C4351: new behavior: elements of array 'x' will be default initialized
 # C4091: 'typedef ': ignored on left of '' when no variable is declared
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /wd4351 /wd4091")
+target_compile_options(trinity-warning-interface
+  INTERFACE
+    /wd4351
+    /wd4091)
 
 if(NOT WITH_WARNINGS)
-  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} /wd4996 /wd4355 /wd4244 /wd4985 /wd4267 /wd4619 /wd4512")
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /wd4996 /wd4355 /wd4244 /wd4985 /wd4267 /wd4619 /wd4512")
+  target_compile_options(trinity-warning-interface
+    INTERFACE
+      /wd4996
+      /wd4355
+      /wd4244
+      /wd4985
+      /wd4267
+      /wd4619
+      /wd4512)
+
   message(STATUS "MSVC: Disabled generic compiletime warnings")
 endif()
 
 if (BUILD_SHARED_LIBS)
   # C4251: needs to have dll-interface to be used by clients of class '...'
   # C4275: non dll-interface class ...' used as base for dll-interface class '...'
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /wd4251 /wd4275")
+  target_compile_options(trinity-warning-interface
+    INTERFACE
+      /wd4251
+      /wd4275)
+
   message(STATUS "MSVC: Enabled shared linking")
 endif()
 
@@ -97,7 +148,10 @@ set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /Zm500")
 # Enable and treat as errors the following warnings to easily detect virtual function signature failures:
 # 'function' : member function does not override any base class virtual member function
 # 'virtual_function' : no override available for virtual member function from base 'class'; function is hidden
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /we4263 /we4264")
+target_compile_options(trinity-warning-interface
+  INTERFACE
+    /we4263
+    /we4264)
 
 # Disable incremental linking in debug builds.
 # To prevent linking getting stuck (which might be fixed in a later VS version).