start throwing error on duplicate label

One less error that's only in the bootstrap phase.

On the other hand, for simplicity I got rid of the ability to override
the Entry label. One less special case, but we're also going further
from the ability to run subsets of layers. We haven't really been
exercising it for a long time, though (commit 7842, March 2021 when we
made baremetal the default).

1 files changed, 0 insertions, 4 deletions

diff --git a/subx.md b/subx.md
index d2b9ad50..1d281ced 100644
--- a/subx.md
+++ b/subx.md
@@ -138,10 +138,6 @@ Functions are called using the following syntax:
 Function arguments must be either literals (integers or strings) or a reg/mem
 operand using the syntax in the previous section.
 
-A special label on Linux is `Entry`, which can be used to specify/override the
-entry point of the program. It doesn't have to be unique, and the latest
-definition will override earlier ones.
-
 Another special pair of labels are the block delimiters `{` and `}`. They can
 be nested, and jump instructions can take arguments `loop` or `break` that
 jump to the enclosing `{` and `}` respectively.