Fix mimalloc build failure with musl and release mode

Author: reigadegr

libmimalloc-sys/build.rs

@@ -6,6 +6,7 @@ fn main() {
     build.include("c_src/mimalloc/include");
     build.include("c_src/mimalloc/src");
     build.file("c_src/mimalloc/src/static.c");
+    build.flag("-Wno-error=date-time");
 
     let target_os = env::var("CARGO_CFG_TARGET_OS").expect("target_os not defined!");
     let target_family = env::var("CARGO_CFG_TARGET_FAMILY").expect("target_family not defined!");