syntax_data: {"ast_node_type":"variable","tokens":[{"end":58,"kind":"keyword","start":0,"text":"if"}]}
source_snippet:     if let Some(libcpp) = option_env!("LLVM_SYS_LIBCPP") {
context_before: fn get_system_libcpp() -> Option<&'static str> {
context_after:         // Use the library defined by the caller, if provided.