diff --git a/Makefile b/Makefile
index b2eb853..50a1d5f 100644
--- a/Makefile
+++ b/Makefile
@@ -14,7 +14,9 @@ all: $(BUILD)/tbm
 
 CFLAGS += -Iinclude
 CFLAGS += -Wall -Wundef -Wextra -Wshadow -Wimplicit-function-declaration
-CFLAGS += -Wredundant-decls -Wmissing-prototypes -Wstrict-prototypes
+CFLAGS += -Wredundant-decls -Wmissing-prototypes -Wstrict-prototypes -pedantic
+
+CFLAGS += -std=c99
 CFLAGS += -Os
 LDFLAGS += -Os