diff --git a/headers/posix/stdlib.h b/headers/posix/stdlib.h
index eb1d02398d..d1db4ab5db 100644
--- a/headers/posix/stdlib.h
+++ b/headers/posix/stdlib.h
@@ -79,7 +79,7 @@ extern long		a64l(const char *string);
 extern char		**environ;
 extern int		clearenv(void);
 extern char		*getenv(const char *name);
-extern int		putenv(const char *string);
+extern int		putenv(char *string);
 extern int		setenv(char const *name, char const *value, int rewrite);
 extern int		unsetenv(const char *name);
 
diff --git a/src/system/libroot/posix/stdlib/env.cpp b/src/system/libroot/posix/stdlib/env.cpp
index e811eeb6f5..bc155f0c55 100644
--- a/src/system/libroot/posix/stdlib/env.cpp
+++ b/src/system/libroot/posix/stdlib/env.cpp
@@ -304,7 +304,7 @@ unsetenv(const char *name)
 
 
 int
-putenv(const char *string)
+putenv(char *string)
 {
 	char *value = strchr(string, '=');
 	status_t status;