aider: Added check_for_ctags method to RepoMap class and updated __init__ method to set use_ctags to False if check_for_ctags returns False.

# Context:
USER: add a check_for_ctags method that: makes a tempdir with hello.py that defines a hello func. call get_tags on that and catch any error and return false. otherwise true.
ASSISTANT: I will add a `check_for_ctags` method to the `RepoMap` class in the `aider/repomap.py` file. This method will create a temporary directory with a `hello.py` file that defines a `hello` function. It will then call the `get_tags` method on that file, catch any errors, and return `False` if there's an error or `True` otherwise.

Here's the change:

```python
aider/repomap.py
<<<<<<< ORIGINAL
import os
import json
import sys
import subprocess
import tiktoken
=======
import os
import json
import sys
import subprocess
import tiktoken
import tempfile
>>>>>>> UPDATED
```

```python
aider/repomap.py
<<<<<<< ORIGINAL
class RepoMap:
    ctags_cmd = ["ctags", "--fields=+S", "--extras=-F", "--output-format=json"]

    def __init__(self, use_ctags=True, root=None, main_model="gpt-4"):
=======
class RepoMap:
    ctags_cmd = ["ctags", "--fields=+S", "--extras=-F", "--output-format=json"]

    def __init__(self, use_ctags=True, root=None, main_model="gpt-4"):
        if not self.check_for_ctags():
            use_ctags = False
>>>>>>> UPDATED
```

```python
aider/repomap.py
<<<<<<< ORIGINAL
        return tags

if __name__ == "__main__":
    rm = RepoMap()
    res = rm.get_tags_map(sys.argv[1:])
    print(res)
=======
    def check_for_ctags(self):
        try:
            with tempfile.TemporaryDirectory() as tempdir:
                hello_py = os.path.join(tempdir, "hello.py")
                with open(hello_py, "w") as f:
                    f.write("def hello():\n    print('Hello, world!')\n")
                self.get_tags(hello_py)
        except Exception:
            return False
        return True

if __name__ == "__main__":
    rm = RepoMap()
    res = rm.get_tags_map(sys.argv[1:])
    print(res)
>>>>>>> UPDATED
```

This adds the `check_for_ctags` method to the `RepoMap` class and updates the `__init__` method to set `use_ctags` to `False` if `check_for_ctags` returns `False`.

aider/repomap.py

@@ -3,6 +3,7 @@ import json
 import sys
 import subprocess
 import tiktoken
+import tempfile
 
 from aider import prompts
 
@@ -50,6 +51,8 @@ class RepoMap:
     ctags_cmd = ["ctags", "--fields=+S", "--extras=-F", "--output-format=json"]
 
     def __init__(self, use_ctags=True, root=None, main_model="gpt-4"):
+        if not self.check_for_ctags():
+            use_ctags = False
         if not root:
             root = os.getcwd()
 
@@ -162,10 +165,19 @@ class RepoMap:
         # Update the cache
         TAGS_CACHE[cache_key] = {"mtime": file_mtime, "tags": tags}
 
-        return tags
-
+    def check_for_ctags(self):
+        try:
+            with tempfile.TemporaryDirectory() as tempdir:
+                hello_py = os.path.join(tempdir, "hello.py")
+                with open(hello_py, "w") as f:
+                    f.write("def hello():\n    print('Hello, world!')\n")
+                self.get_tags(hello_py)
+        except Exception:
+            return False
+        return True
 
 if __name__ == "__main__":
     rm = RepoMap()
     res = rm.get_tags_map(sys.argv[1:])
     print(res)
+    print(res)