diff --git a/justfile b/justfile
index ab443b5..4dcaaa0 100644
--- a/justfile
+++ b/justfile
@@ -1,5 +1,5 @@
 CC := "zig cc"
-CFLAGS := "-pedantic -Wall -Wextra -Wno-override-init -O0 -g -fno-omit-frame-pointer -fno-inline"
+CFLAGS := "-pedantic -Wall -Wextra -Wno-override-init -O0 -g -fno-omit-frame-pointer -fno-inline -std=c99"
 LDFLAGS := "-lcriterion"
 TESTBIN := "/tmp/all_tests"