Undo two segfault fixes in 1991/dds - INABIAF

I noticed that I unfortunately fixed two segfaults that should not have
been fixed: if the input file cannot be opened for reading or the output
file cannot be opened for writing this program will crash. Changed both
dds.c and dds.alt.c (which I added to work with clang). The original fix
that allows this entry to work at all (segfaulted always) remains in
both versions.

Updated README.md and bugs.md. In bugs.md I also added a note that the
compiled code uses gets() not fgets() - whatever it might be worth.

bugs.md

@@ -542,6 +542,23 @@ This will be fixed in time but it's noted here for now.
 
 # 1991
 
+## [1991/dds](1991/dds/dds.c) ([README.md)(1991/dds/README.md))
+## [1991/dds.alt](1991/dds/dds.alt.c) ([README.md)(1991/dds/README.md))
+## STATUS: INABIAF - please **DO NOT** fix
+
+If the BASIC file cannot be opened for reading or the output file cannot be
+opened for writing the program will crash. This is not a bug but a feature.
+Please do not fix this except for the challenge.
+
+Please also note that for `clang` you have to use [dds.alt](1991/dds/dds.alt.c) not
+[dds.c](1991/dds/dds.c).
+
+## STATUS: uses gets() - change to fgets() if possible
+
+That being said the compiled code uses `gets()` not `fgets()`. Can you fix this?
+You might find that the `s` array is relevant but if you do change it please
+make sure to test all functionality!
+
 ## [1991/westley](1991/westley/westley.c) ([README.md](1991/westley/README.md))
 ## STATUS: INABIAF - please **DO NOT** fix
 
@@ -553,6 +570,7 @@ Please don't try and fix it as it's not a bug and was actually documented as a
 possibility. Can you find out how?
 
 
+
 # 1992
 
 ## [1992/buzzard.1](1992/buzzard.1/buzzard.1.c) ([README.md](1992/buzzard.1/README.md))