Squashed commit upgrading to mbedtls-2.22.0

Squash merging branch import/mbedtls-2.22.0

5cab03377186 ("mk/clang.mk: define libgcc$(sm)")
3607a5386a72 ("core: mbedtls: enable MBEDTLS_ECDH_LEGACY_CONTEXT")
896c8845bbda ("mbedtls: remove file md_wrap.c from build")
400b2af54fa0 ("libmbedtls: mbedtls_mpi_exp_mod(): optimize mempool usage")
777827c7af3d ("libmbedtls: mbedtls_mpi_exp_mod(): reduce stack usage")
549e4600678e ("libmbedtls: preserve mempool usage on reinit")
02d636083fe2 ("libmbedtls: mbedtls_mpi_exp_mod() initialize W")
d2ac2b3c92bf ("libmbedtls: fix no CRT issue")
f550879d5be2 ("libmbedtls: add interfaces in mbedtls for context memory operation")
219173d807ce ("libmedtls: mpi_miller_rabin: increase count limit")
7930b0b6b5e4 ("libmbedtls: add mbedtls_mpi_init_mempool()")
78af9fdc120f ("libmbedtls: make mbedtls_mpi_mont*() available")
8f7357271cc2 ("libmbedtls: refine mbedtls license header")
c5993878881f ("mbedtls: configure mbedtls to reach for config")
6f9c587783af ("mbedtls: remove default include/mbedtls/config.h")
3d3bd3b12752 ("Import mbedtls-2.22.0")

Signed-off-by: Jerome Forissier <jerome@forissier.org>
Acked-by: Jens Wiklander <jens.wiklander@linaro.org>
diff --git a/lib/libmbedtls/mbedtls/library/md4.c b/lib/libmbedtls/mbedtls/library/md4.c
index 8156d0b..943c953 100644
--- a/lib/libmbedtls/mbedtls/library/md4.c
+++ b/lib/libmbedtls/mbedtls/library/md4.c
@@ -35,6 +35,7 @@
 
 #include "mbedtls/md4.h"
 #include "mbedtls/platform_util.h"
+#include "mbedtls/error.h"
 
 #include <string.h>
 
@@ -253,7 +254,7 @@
                             const unsigned char *input,
                             size_t ilen )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t fill;
     uint32_t left;
 
@@ -323,7 +324,7 @@
 int mbedtls_md4_finish_ret( mbedtls_md4_context *ctx,
                             unsigned char output[16] )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     uint32_t last, padn;
     uint32_t high, low;
     unsigned char msglen[8];
@@ -371,7 +372,7 @@
                      size_t ilen,
                      unsigned char output[16] )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     mbedtls_md4_context ctx;
 
     mbedtls_md4_init( &ctx );