base64: Migrate over to osmocom

This containts the osmocom changes to the mbedtls base64 code
merged in the previous commit.

Change-Id: I82c1bf5f827c8def370dbcb80b146e9e4184c4a3
diff --git a/include/osmocom/core/base64.h b/include/osmocom/core/base64.h
index 0f7233d..f73db0d 100644
--- a/include/osmocom/core/base64.h
+++ b/include/osmocom/core/base64.h
@@ -21,14 +21,10 @@
  *  with this program; if not, write to the Free Software Foundation, Inc.,
  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
-#ifndef MBEDTLS_BASE64_H
-#define MBEDTLS_BASE64_H
+#pragma once
 
 #include <stddef.h>
 
-#define MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL               -0x002A  /**< Output buffer too small. */
-#define MBEDTLS_ERR_BASE64_INVALID_CHARACTER              -0x002C  /**< Invalid character in input. */
-
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -49,7 +45,7 @@
  * \note           Call this function with dlen = 0 to obtain the
  *                 required buffer size in *olen
  */
-int mbedtls_base64_encode( unsigned char *dst, size_t dlen, size_t *olen,
+int osmo_base64_encode( unsigned char *dst, size_t dlen, size_t *olen,
                    const unsigned char *src, size_t slen );
 
 /**
@@ -69,18 +65,9 @@
  * \note           Call this function with *dst = NULL or dlen = 0 to obtain
  *                 the required buffer size in *olen
  */
-int mbedtls_base64_decode( unsigned char *dst, size_t dlen, size_t *olen,
+int osmo_base64_decode( unsigned char *dst, size_t dlen, size_t *olen,
                    const unsigned char *src, size_t slen );
 
-/**
- * \brief          Checkup routine
- *
- * \return         0 if successful, or 1 if the test failed
- */
-int mbedtls_base64_self_test( int verbose );
-
 #ifdef __cplusplus
 }
 #endif
-
-#endif /* base64.h */