Overwrite symlinks for config files

In Makefile, we are trying to remove old symlinks first and then create a symlink.
do the same thing in meson too.

Also, the line of the exception handling for FileExistsError is meaningless
as the above line is taking care of it instead and we shouldn't ignore it if
os.remove and os.symlink doesn't work somehow.

Fixes https://gitlab.freedesktop.org/fontconfig/fontconfig/-/issues/275
diff --git a/conf.d/link_confs.py b/conf.d/link_confs.py
index 5a78d8d..e195095 100644
--- a/conf.d/link_confs.py
+++ b/conf.d/link_confs.py
@@ -21,6 +21,10 @@
         src = os.path.join(args.availpath, link)
         dst = os.path.join(confpath, link)
         try:
+            os.remove(dst)
+        except FileNotFoundError:
+            pass
+        try:
             os.symlink(src, dst)
         except NotImplementedError:
             # Not supported on this version of Windows
@@ -30,5 +34,3 @@
             if platform.system().lower() == 'windows' and e.winerror == 1314:
                 break
             raise
-        except FileExistsError:
-            pass