cpu/avr8_common: add strings.h for compatibility

cpu/avr8_common/avr_libc_extra/include/strings.h

@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2022 Otto-von-Guericke-Universität Magdeburg
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser General
+ * Public License v2.1. See the file LICENSE in the top level directory for more
+ * details.
+ */
+
+/**
+ * @addtogroup cpu_atmega_common
+ *
+ * This is header file provides `strings.h` that is missing in AVR libc for
+ * compatibility.
+ *
+ * @{
+ *
+ * @file
+ * @brief       strings.h
+ *
+ * @author      Marian Buschsieweke <marian.buschsieweke@ovgu.de>
+ */
+
+#include <string.h>
+
+#ifndef STRINGS_H
+#define STRINGS_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief   Same as `memset(dest, 0, n_bytes)`, use `memset()` instead
+ *
+ * @param[in,out]   dest        Memory to clear
+ * @param[in]       n_bytes     Size of memory to clear in bytes
+ */
+static inline void bzero(void *dest, size_t n_bytes)
+{
+    memset(dest, 0, n_bytes);
+}
+
+/**
+ * @brief   Same as `memcmp()`, use `memcmp` instead
+ *
+ * @param[in]   s1      first memory chunk to compare
+ * @param[in]   s2      second memory chunk to compare
+ * @param[in]   n       number of bytes to compare
+ *
+ * @retval  `0`     The first @p n bytes of @p s1 and @p s2 are equal
+ * @retval  `!=0`   The first @p n bytes of @p s1 and @p s2 differ in at least
+ *                  one bit
+ */
+static inline int bcmp(const void *s1, const void *s2, size_t n)
+{
+    return memcmp(s1, s2, n);
+}
+
+/**
+ * @brief   Same as `memmove()`, use `memmove()` or `memcpy()` instead
+ *
+ * @param[in]   src     memory to copy from
+ * @param[out]  dest    memory to copy to
+ * @param[in]   n       number of bytes to copy
+ *
+ * @details @p src and @p dest may overlap
+ *
+ * @note    It is preferred to use the standardize function `memcpy()` for
+ *          non-overlapping memory regions and `memmove()` for overlapping
+ *          memory regions instead of this obsolete function.
+ */
+static inline void bcopy(const void *src, void *dest, size_t n)
+{
+    memmove(dest, src, n);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* STRINGS_H */
+/** @} */