cmake: Added LIBM target for addon builds (#7074)

Author: cwhite911

cmake/modules/build_addon.cmake

@@ -340,3 +340,16 @@ macro(find_OpenMP)
     add_compile_options(-openmp:llvm)
   endif()
 endmacro()
+
+macro(find_M)
+  if(UNIX AND NOT TARGET LIBM)
+    find_library(MATH_LIBRARY m)
+    add_library(LIBM INTERFACE IMPORTED GLOBAL)
+    if(MATH_LIBRARY)
+      set_property(TARGET LIBM PROPERTY INTERFACE_LINK_LIBRARIES ${MATH_LIBRARY})
+    else()
+      # Fallback: allow the linker to resolve -lm by name.
+      set_property(TARGET LIBM PROPERTY INTERFACE_LINK_LIBRARIES m)
+    endif()
+  endif()
+endmacro()