diff --git a/01_ENV/build-c.sh b/01_ENV/build-c.sh
index 64f79e1..0af9db8 100755
--- a/01_ENV/build-c.sh
+++ b/01_ENV/build-c.sh
@@ -1,4 +1,4 @@
 #!/usr/bin/env bash
 bash clean.sh
-clang-6.0 -c func1.c main.c -v
-clang-6.0 -s func1.o main.o -v
+clang-6.0 -c func1.c main.c -B /usr/include/ -lm
+clang-6.0 -s func1.o main.o
diff --git a/01_ENV/func1.c b/01_ENV/func1.c
index db6583d..0dc0564 100644
--- a/01_ENV/func1.c
+++ b/01_ENV/func1.c
@@ -1,5 +1,5 @@
 #include <stdio.h>
-#include "math.h"
+#include <math.h>
 
 #define func1