diff --git a/archivers/lz4/Portfile b/archivers/lz4/Portfile
index 3ff574a5648..08d12fefc21 100644
--- a/archivers/lz4/Portfile
+++ b/archivers/lz4/Portfile
@@ -30,6 +30,11 @@ patchfiles          gen_manual.patch
 
 use_configure       no
 
+compiler.c_standard 1999
+
+# bench_functions.c: error: ‘for’ loop initial declaration used outside C99 mode
+configure.cflags-append     -std=c99
+
 build.args-append           CC=${configure.cc} \
                             CXX=${configure.cxx} \
                             PREFIX=${prefix} \