[ML] Suppress Clang -Wunused-macros for test targets only

BOOST_TEST_MODULE and BOOST_TEST_NO_MAIN are consumed by the
subsequent #include <boost/test/unit_test.hpp> but Clang flags
them as unused since they're not referenced directly in source.
Suppress for test targets only via target_compile_options in
ml_add_test_executable, rather than globally.

Made-with: Cursor

Author: edsavage

cmake/compiler/clang.cmake

@@ -37,7 +37,6 @@ list(APPEND ML_C_FLAGS
   "-Wno-switch-default"
   "-Wno-unknown-warning-option"
   "-Wno-unreachable-code"
-  "-Wno-unused-macros"
   "-Wno-used-but-marked-unused"
   ${ML_COVERAGE})
 

cmake/compiler/msvc.cmake

@@ -27,10 +27,14 @@ list(APPEND ML_COMPILE_DEFINITIONS
   _WIN32_WINNT=0x0601
   Windows)
 
+# Treat SYSTEM include directories as external — suppress warnings from
+# third-party headers (Boost, Eigen, PyTorch, etc.).  Requires MSVC 17.0+.
+set(CMAKE_INCLUDE_SYSTEM_FLAG_CXX "/external:I ")
 list(APPEND ML_C_FLAGS
   "/X"
   "/nologo"
   "/W4"
+  "/external:W0"
   "/EHsc"
   "/Gw"
   "/Zc:inline"

cmake/functions.cmake

@@ -382,6 +382,12 @@ function(ml_add_test_executable _target)
 
   set_property(TARGET ml_test_${_target} PROPERTY POSITION_INDEPENDENT_CODE TRUE)
 
+  # Boost.Test's BOOST_TEST_MODULE / BOOST_TEST_NO_MAIN macros are consumed
+  # by the subsequent #include <boost/test/unit_test.hpp> but Clang flags
+  # them as unused.  Suppress for test targets only.
+  target_compile_options(ml_test_${_target} PRIVATE
+    $<$<CXX_COMPILER_ID:AppleClang,Clang>:-Wno-unused-macros>)
+
   if(ML_PCH)
     target_precompile_headers(ml_test_${_target} PRIVATE
       <string>