fix: SLIC3R_PCH=OFF now builds on Windows, allowing compiler caching (#15552)

src/libslic3r/CMakeLists.txt

@@ -665,6 +665,13 @@ if(SLIC3R_PROFILE)
     target_link_libraries(libslic3r PRIVATE Shiny)
 endif()
 
+if (WIN32)
+    # Public, since BlacklistedLibraryCheck.hpp includes windows.h. Empty
+    # WIN32_LEAN_AND_MEAN matches the sources that define it themselves; bare
+    # NOMINMAX matches the one libigl already passes.
+    target_compile_definitions(libslic3r PUBLIC "WIN32_LEAN_AND_MEAN=" "NOMINMAX")
+endif ()
+
 if (SLIC3R_PCH AND NOT SLIC3R_SYNTAXONLY)
     add_precompiled_header(libslic3r pchheader.hpp FORCEINCLUDE)
 endif ()