bazel: bison patch resolves repo name with repo_name(), not hardcoded

Gemini flagged the hardcoded `external/bison+/lib` canonical repo name as
non-portable (Bazel 7 uses `~`, Bazel 8 `+`). Correct in principle — this
repo pins Bazel 8.6.0 so `+` is right for what ships, but the patch is
headed upstream (bison@3.8.2.bcr.8) where it must survive both.

Gemini's suggested `native.repo_name()` does NOT work here: `native` is
undefined at BUILD-file top level (verified: "name 'native' is not
defined"), and BISON_COPTS is a top-level assignment. The bare builtin
`repo_name()` is the one callable there — verified in a scratch Bazel
8.6.0 module that it returns the canonical name with the separator
(`depb+`), so bison resolves to `bison+`, byte-identical to the previous
hardcoding on Bazel 8 and correct on Bazel 7.1+.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Signed-off-by: Øyvind Harboe <oyvind.harboe@zylin.com>

Author: oharboe

bazel/bison-patches/0001-gnulib-wrapper-headers-use-I-not-isystem.patch

@@ -37,8 +37,8 @@ diff --git a/BUILD.bazel b/BUILD.bazel
 +# listed as both -I and -isystem stays -isystem, so the -isystem form must
 +# go entirely). This restores autotools' AM_CPPFLAGS = -I./lib ordering.
 +BISON_COPTS = [
-+    "-Iexternal/bison+/lib",
-+    "-I$(BINDIR)/external/bison+/lib",
++    "-Iexternal/" + repo_name() + "/lib",
++    "-I$(BINDIR)/external/" + repo_name() + "/lib",
 +] + select({
      "@rules_cc//cc/compiler:clang": [
          "-w",