Nullptr checks

FossilOrigin-Name: 2407ab3be7e0dc0d94290b54c424fc3a9a5f945784dda05fb9f6015c63589766

src/emoji.c

@@ -29,6 +29,7 @@
 
 char* emojify(char* content, struct mstdnt_emoji* emos, size_t emos_len)
 {
+    if (!(content && emos && emos_len)) return NULL;
     size_t sc_len;
     char* oldres = NULL;
     char* res = content;

src/status.c

@@ -396,6 +396,8 @@ char* reformat_status(struct session* ssn,
 
 char* greentextify(char* content)
 {
+    if (!content) return NULL;
+    
     const char* error;
     int erroffset;
     int rc;