CMake: Update a comment

The stringop-overflow warning is active with both GCC and Clang
in the master branch and was not triggered by our build bots so
update the comment to reflect that.

```
epan/dissectors/packet-lwm.c:464:31: error: writing 16 bytes into a region of size 0 [-Werror=stringop-overflow=]
  464 |                     vector[i] ^= text_dec[i];
      |                     ~~~~~~~~~~^~~~~~~~~~~~~~
epan/dissectors/packet-lwm.c:419:21: note: at offset 192 into destination object ‘nwkSecurityVector’ of size 16
  419 |             guint32 nwkSecurityVector[4];
      |                     ^~~~~~~~~~~~~~~~~
```

CMakeLists.txt

@@ -640,22 +640,21 @@ else() # ! MSVC
 		-Wlogical-op		# GCC-only
 		#
 		# Disable errors unconditionally for some static analysis warnings
-		# that are dormant at lower optimizations levels and also
+		# that are dormant at lower optimizations levels or active only in
+		# bleeding edge versions of a compiler and possibly also
 		# prone to false positives and compiler bugs. This is
 		# a big nuisance because the warning is dormant and a low
 		# priority target for action. That is very disruptive
 		# with -Werror enabled (the default on the master branch).
 		#
+		-Wno-error=stringop-overflow=
+		#
 		# XXX Now that we have a CI job with Release build type (using
 		# -O3 optimization level) the dormancy issue should be ameliorated
 		# so comment out these exceptions to re-evaluate the impact.
 		#-Wno-error=maybe-uninitialized
 		#-Wno-error=alloc-size-larger-than=
 		#
-		# XXX We still don't have a CI release build using Clang so keep
-		# Werror disabled with Wstringop-overflow for the reasons stated above.
-		-Wno-error=stringop-overflow=
-		#
 		# Updating external dependencies can introduce new deprecations.
 		# Also fixing new internal deprecations takes time.
 		# We want to be able to build with -Werror in that case. New