Add interface library for project-wide compile options

Previously we were relying on the use of add_compile_options and
add_compile_definitions for defining compiler definitions and options for
the entire project. This commit replaces that behaviour by defining a new
mrtrix::common INTERFACE library that links to all targets in the
project (the library is linked to mrtrix::core). This is more idiomatic
and prevents the propagation of compiler definitions to targets that do
not link to mrtrix::core (useful when compiling MRtrix3 as a subproject
of anothe project).

CMakeLists.txt

@@ -91,35 +91,35 @@ if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/.git AND NOT EXISTS ${CMAKE_CURRENT_SOURCE
         "and then run `pre-commit install` from the ${CMAKE_CURRENT_SOURCE_DIR} directory.")
 endif()
 
-
-# Allow compilation of big object of files in debug mode on MINGW
-if(MINGW AND CMAKE_BUILD_TYPE MATCHES "Debug")
-    add_compile_options(-Wa,-mbig-obj)
-endif()
-
-add_compile_definitions(
+add_library(mrtrix-common INTERFACE)
+add_library(mrtrix::common ALIAS mrtrix-common)
+target_compile_definitions(mrtrix-common INTERFACE
     MRTRIX_BUILD_TYPE="${CMAKE_BUILD_TYPE}"
     $<$<PLATFORM_ID:Windows>:MRTRIX_WINDOWS>
     $<$<PLATFORM_ID:Darwin>:MRTRIX_MACOSX>
     $<$<PLATFORM_ID:FreeBSD>:MRTRIX_FREEBSD>
 )
 
-if(MRTRIX_STL_DEBUGGING AND $<NOT:$<CONFIG:Debug>>)
-    if(MSVC)
-        add_compile_definitions(_ITERATOR_DEBUG_LEVEL=1)
-    elseif(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
-        add_compile_options(_LIBCPP_DEBUG)
-    elseif(CMAKE_CXX_COMPILER_ID MATCHES "GNU")
-        add_compile_options(_GLIBCXX_DEBUG _GLIBCXX_DEBUG_PEDANTIC)
-    endif()
+if(MRTRIX_STL_DEBUGGING AND NOT CMAKE_BUILD_TYPE STREQUAL "Debug")
+    message(STATUS "Enabling STL debug mode")
+    target_compile_definitions(mrtrix-common INTERFACE
+        $<$<CXX_COMPILER_ID:MSVC>:_ITERATOR_DEBUG_LEVEL=1>
+        $<$<CXX_COMPILER_ID:GNU>:_GLIBCXX_DEBUG, _GLIBCXX_DEBUG_PEDANTIC>
+        $<$<CXX_COMPILER_ID:Clang>:-D_LIBCPP_DEBUG>
+    )
 endif()
 
 if(MRTRIX_WARNINGS_AS_ERRORS)
-    if (MSVC)
-        add_compile_options(/WX)
-    else()
-        add_compile_options(-Werror)
-    endif()
+    message(STATUS "Enabling warnings as errors")
+    target_compile_options(mrtrix-common INTERFACE
+        $<$<CXX_COMPILER_ID:MSVC>:/WX>
+        $<$<CXX_COMPILER_ID:GNU,Clang>:-Werror>
+    )
+endif()
+
+# Allow compilation of big object of files in debug mode on MINGW
+if(MINGW AND CMAKE_BUILD_TYPE MATCHES "Debug")
+    target_compile_options(mrtrix-common INTERFACE -Wa,-mbig-obj)
 endif()
 
 

core/CMakeLists.txt

@@ -87,6 +87,7 @@ target_link_libraries(mrtrix-core PUBLIC
     ZLIB::ZLIB
     ${FFTW_LIBRARIES}
     mrtrix::core-version-lib
+    mrtrix::common
     Threads::Threads
     ${FFTW_LIBRARIES}
 )