diff --git a/mongoose.c b/mongoose.c
index 54f880c8..fbf87bfd 100644
--- a/mongoose.c
+++ b/mongoose.c
@@ -9833,7 +9833,7 @@ static void mg_tls_encrypt(struct mg_connection *c, const uint8_t *msg,
 #if CHACHA20
   (void) tag;  // tag is only used in aes gcm
   {
-    uint8_t *enc = malloc(8192);
+    uint8_t *enc = (uint8_t *) malloc(8192);
     if (enc == NULL) {
       mg_error(c, "TLS OOM");
       return;
@@ -11019,8 +11019,8 @@ static void core_block(const uint32_t *restrict start,
 
 static void xor_block(uint8_t *restrict dest, const uint8_t *restrict source,
                       const uint32_t *restrict pad, unsigned int chunk_size) {
-  unsigned int i, full_blocks = chunk_size / sizeof(uint32_t);
-  // have to be carefull, we are going back from uint32 to uint8, so endianess
+  unsigned int i, full_blocks = chunk_size / (unsigned int) sizeof(uint32_t);
+  // have to be carefull, we are going back from uint32 to uint8, so endianness
   // matters again
   xor32_blocks(dest, source, pad, full_blocks)
 
diff --git a/mongoose.h b/mongoose.h
index 359e5261..6f2f5b36 100644
--- a/mongoose.h
+++ b/mongoose.h
@@ -1965,11 +1965,11 @@ extern "C" {
  if possible, carefully pick your associated data.
 */
 
-// Make sure we are either nested in C++ or running in a C99+ compiler
+/* Make sure we are either nested in C++ or running in a C99+ compiler
 #if !defined(__cplusplus) && !defined(_MSC_VER) && \
     (!defined(__STDC_VERSION__) || __STDC_VERSION__ < 199901L)
 #error "C99 or newer required"
-#endif
+#endif */
 
 // #if CHAR_BIT > 8
 // #    error "Systems without native octals not suppoted"
diff --git a/src/tls_builtin.c b/src/tls_builtin.c
index 51b8f673..c01fd2c8 100644
--- a/src/tls_builtin.c
+++ b/src/tls_builtin.c
@@ -397,7 +397,7 @@ static void mg_tls_encrypt(struct mg_connection *c, const uint8_t *msg,
 #if CHACHA20
   (void) tag;  // tag is only used in aes gcm
   {
-    uint8_t *enc = malloc(8192);
+    uint8_t *enc = (uint8_t *) malloc(8192);
     if (enc == NULL) {
       mg_error(c, "TLS OOM");
       return;
diff --git a/src/tls_chacha20.c b/src/tls_chacha20.c
index 2abf74f9..7be53023 100644
--- a/src/tls_chacha20.c
+++ b/src/tls_chacha20.c
@@ -200,8 +200,8 @@ static void core_block(const uint32_t *restrict start,
 
 static void xor_block(uint8_t *restrict dest, const uint8_t *restrict source,
                       const uint32_t *restrict pad, unsigned int chunk_size) {
-  unsigned int i, full_blocks = chunk_size / sizeof(uint32_t);
-  // have to be carefull, we are going back from uint32 to uint8, so endianess
+  unsigned int i, full_blocks = chunk_size / (unsigned int) sizeof(uint32_t);
+  // have to be carefull, we are going back from uint32 to uint8, so endianness
   // matters again
   xor32_blocks(dest, source, pad, full_blocks)
 
diff --git a/src/tls_chacha20.h b/src/tls_chacha20.h
index 4071a199..f77e08f3 100644
--- a/src/tls_chacha20.h
+++ b/src/tls_chacha20.h
@@ -26,11 +26,11 @@ extern "C" {
  if possible, carefully pick your associated data.
 */
 
-// Make sure we are either nested in C++ or running in a C99+ compiler
+/* Make sure we are either nested in C++ or running in a C99+ compiler
 #if !defined(__cplusplus) && !defined(_MSC_VER) && \
     (!defined(__STDC_VERSION__) || __STDC_VERSION__ < 199901L)
 #error "C99 or newer required"
-#endif
+#endif */
 
 // #if CHAR_BIT > 8
 // #    error "Systems without native octals not suppoted"