diff --git a/programs/pkey/dh_client.c b/programs/pkey/dh_client.c
index be0b6e9..5a2c30f 100644
--- a/programs/pkey/dh_client.c
+++ b/programs/pkey/dh_client.c
@@ -20,6 +20,7 @@
 #include "mbedtls/build_info.h"
 
 #include "mbedtls/platform.h"
+/* md.h is included this early since MD_CAN_XXX macros are defined there. */
 #include "mbedtls/md.h"
 
 #if defined(MBEDTLS_AES_C) && defined(MBEDTLS_DHM_C) && \
diff --git a/programs/pkey/dh_server.c b/programs/pkey/dh_server.c
index b883653..c940be0 100644
--- a/programs/pkey/dh_server.c
+++ b/programs/pkey/dh_server.c
@@ -20,7 +20,7 @@
 #include "mbedtls/build_info.h"
 
 #include "mbedtls/platform.h"
-// md.h is included this early since MD_CAN_XXX macros are defined there.
+/* md.h is included this early since MD_CAN_XXX macros are defined there. */
 #include "mbedtls/md.h"
 
 #if defined(MBEDTLS_AES_C) && defined(MBEDTLS_DHM_C) && \
diff --git a/programs/pkey/pk_sign.c b/programs/pkey/pk_sign.c
index 2e9b2d8..82cb6a1 100644
--- a/programs/pkey/pk_sign.c
+++ b/programs/pkey/pk_sign.c
@@ -20,7 +20,7 @@
 #include "mbedtls/build_info.h"
 
 #include "mbedtls/platform.h"
-// md.h is included this early since MD_CAN_XXX macros are defined there.
+/* md.h is included this early since MD_CAN_XXX macros are defined there. */
 #include "mbedtls/md.h"
 
 #if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_ENTROPY_C) ||  \
diff --git a/programs/pkey/pk_verify.c b/programs/pkey/pk_verify.c
index bdeb559..0c549e0 100644
--- a/programs/pkey/pk_verify.c
+++ b/programs/pkey/pk_verify.c
@@ -20,7 +20,7 @@
 #include "mbedtls/build_info.h"
 
 #include "mbedtls/platform.h"
-// md.h is included this early since MD_CAN_XXX macros are defined there.
+/* md.h is included this early since MD_CAN_XXX macros are defined there. */
 #include "mbedtls/md.h"
 
 #if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_MD_C) || \
diff --git a/programs/pkey/rsa_sign.c b/programs/pkey/rsa_sign.c
index 8ba3e7d..64375e9 100644
--- a/programs/pkey/rsa_sign.c
+++ b/programs/pkey/rsa_sign.c
@@ -20,7 +20,7 @@
 #include "mbedtls/build_info.h"
 
 #include "mbedtls/platform.h"
-// md.h is included this early since MD_CAN_XXX macros are defined there.
+/* md.h is included this early since MD_CAN_XXX macros are defined there. */
 #include "mbedtls/md.h"
 
 #if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_RSA_C) ||  \
diff --git a/programs/pkey/rsa_sign_pss.c b/programs/pkey/rsa_sign_pss.c
index fe3de03..03882cd 100644
--- a/programs/pkey/rsa_sign_pss.c
+++ b/programs/pkey/rsa_sign_pss.c
@@ -20,7 +20,7 @@
 #include "mbedtls/build_info.h"
 
 #include "mbedtls/platform.h"
-// md.h is included this early since MD_CAN_XXX macros are defined there.
+/* md.h is included this early since MD_CAN_XXX macros are defined there. */
 #include "mbedtls/md.h"
 
 #if !defined(MBEDTLS_MD_C) || !defined(MBEDTLS_ENTROPY_C) ||  \
diff --git a/programs/pkey/rsa_verify.c b/programs/pkey/rsa_verify.c
index ccdf13e..d525010 100644
--- a/programs/pkey/rsa_verify.c
+++ b/programs/pkey/rsa_verify.c
@@ -20,7 +20,7 @@
 #include "mbedtls/build_info.h"
 
 #include "mbedtls/platform.h"
-// md.h is included this early since MD_CAN_XXX macros are defined there.
+/* md.h is included this early since MD_CAN_XXX macros are defined there. */
 #include "mbedtls/md.h"
 
 #if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_RSA_C) ||  \
diff --git a/programs/pkey/rsa_verify_pss.c b/programs/pkey/rsa_verify_pss.c
index d7efa65..e21e927 100644
--- a/programs/pkey/rsa_verify_pss.c
+++ b/programs/pkey/rsa_verify_pss.c
@@ -20,7 +20,7 @@
 #include "mbedtls/build_info.h"
 
 #include "mbedtls/platform.h"
-// md.h is included this early since MD_CAN_XXX macros are defined there.
+/* md.h is included this early since MD_CAN_XXX macros are defined there. */
 #include "mbedtls/md.h"
 
 #if !defined(MBEDTLS_MD_C) || !defined(MBEDTLS_ENTROPY_C) ||  \