CMake: Fix compile error due to missing `-lm` for deploy-stub

pandatool/src/deploy-stub/CMakeLists.txt

@@ -18,6 +18,7 @@ elseif(IS_LINUX OR IS_FREEBSD)
     INSTALL_RPATH "$ORIGIN"
     BUILD_WITH_INSTALL_RPATH ON)
   target_link_options(deploy-stub PRIVATE -Wl,--disable-new-dtags -Wl,-z,origin -rdynamic)
+  target_link_libraries(deploy-stub m)
 endif()
 
 target_link_libraries(deploy-stub Python::Python)