ci: validate every member with mcpp 2026.10.1.2; latest_mcpp -> 2026.10.1.2

.github/workflows/validate.yml

@@ -421,7 +421,13 @@ env:
   # the build compiles, a selected workspace member declares as the root
   # (mcpp-community/mcpp#747), and the clang MSVC row states its compiler
   # version (#746).
-  MCPP_VERSION: "2026.10.1.1"
+  #
+  # 2026.10.1.2 (mcpp-community/mcpp#754): every package's BMIs lie below its
+  # own directory in the build directory except the root's, and a unit reads
+  # one module map of what it reaches; every unit of an ELF target is compiled
+  # position-independent; `mcpp pack` states its build; `[build] jobs` bounds
+  # `test` and `pack` (#751, #753).
+  MCPP_VERSION: "2026.10.1.2"
 
 jobs:
   lint:

index.toml

@@ -166,7 +166,15 @@
 # that reads mcpp's output captures both streams (`tests/run_members.sh`).
 # A host module of an index package is compiled once per key and kept in the
 # global cache, which every member with a build program now exercises.
+# ── 2026-10-01: latest_mcpp -> 2026.10.1.2, min_mcpp unchanged ─────────────
+#
+# Moved in the pull request that moves validate.yml's pin to 2026.10.1.2,
+# which runs every member on every platform with it. The release changes no
+# descriptor grammar. A dependency's BMIs now lie below its package's
+# directory, and every unit of an ELF target is compiled with -fPIC, so every
+# member is compiled once more and its global cache entries are refilled; no
+# check here reads a BMI path.
 [index]
 spec        = "1"
 min_mcpp    = "2026.9.18.3"
-latest_mcpp = "2026.10.1.1"
+latest_mcpp = "2026.10.1.2"