bryan-minimal · Jun 18, 2026 · Jun 11, 2026 · Jun 11, 2026 · Jun 11, 2026 · Jun 16, 2026
@@ -9,7 +9,13 @@ case $(uname -m) in
   aarch64) MARCH="-march=armv8-a" ;;
   *)       MARCH="" ;;
 esac
-export CFLAGS="$MARCH -O2 -pipe -gno-record-gcc-switches -Wl,--build-id=none -ffile-prefix-map=$(pwd)=/builddir"
+# -Wno-error=discarded-qualifiers: glibc 2.43's ISO C23 const-preserving
+# bsearch/strchr-family return const for const args; elfutils assigns those to
+# plain pointers (libcpu/riscv_disasm.c known_csrs bsearch) under its default-on
+# -Werror. elfutils' configure has no --disable-werror in this version, but
+# automake emits `$(AM_CFLAGS) $(CFLAGS)`, so a CFLAGS flag lands after
+# elfutils' AM_CFLAGS -Werror and wins. Same glibc-2.43 C23 FTBFS class as #238.
+export CFLAGS="$MARCH -O2 -pipe -gno-record-gcc-switches -Wl,--build-id=none -ffile-prefix-map=$(pwd)=/builddir -Wno-error=discarded-qualifiers"
 export LDFLAGS="-Wl,--build-id=none"
 export ARFLAGS=Drc
 export CXXFLAGS="${CFLAGS}"

@@ -32,6 +32,34 @@ export LDFLAGS="-Wl,--build-id=none"
 export CXXFLAGS="${CFLAGS}"
 export ARFLAGS=Drc
 
+# glibc 2.43 implements ISO C23 const-preserving string macros: strchr,
+# strrchr, strstr, memchr, etc. now return a `const char *` when given a
+# `const char *`. gcc-15.2.0 predates this, so its libgomp source
+# (libgomp/affinity-fmt.c: `char *q = strchr (p + 1, '}');`) assigns the
+# result to a plain `char *` and trips -Werror=discarded-qualifiers, failing
+# the build. The pointer is never written through (only used for `q - p`), so
+# this is a source-pedantry mismatch, not a runtime bug.
+#
+# Downgrade ONLY that one warning (everything else stays -Werror), for gcc's
+# own build only — the produced compiler is unaffected. CFLAGS_FOR_TARGET is
+# the documented knob for target libraries like libgomp (BOOT_CFLAGS/CFLAGS
+# don't reach them); see https://gcc.gnu.org/install/build.html. CFLAGS keeps
+# it for gcc proper defensively.
+#
+# This is the interim escape hatch; gcc-16.1.0 fixes this upstream (it builds
+# cleanly against glibc 2.43 — LFS pairs them with no workaround), so the
+# clean follow-up is to bump gcc to 16. Refs:
+#   - glibc 2.43 C23 const-preserving macros:
+#       https://lists.gnu.org/archive/html/info-gnu/2026-01/msg00005.html
+#   - upstream gcc libgomp fix ("Fix GCC build after glibc@cd748a6"):
+#       https://www.mail-archive.com/gcc-patches@gcc.gnu.org/msg389139.html
+#   - LFS GCC-16.1.0 (builds against glibc 2.43, no const workaround):
+#       https://www.linuxfromscratch.org/lfs/view/development/chapter08/gcc.html
+export CFLAGS="${CFLAGS} -Wno-error=discarded-qualifiers"
+export CXXFLAGS="${CFLAGS}"
+export CFLAGS_FOR_TARGET="${CFLAGS}"
+export CXXFLAGS_FOR_TARGET="${CXXFLAGS}"
+
 ../configure \
              --prefix=/usr                      \
              --libdir=/usr/lib                   \

@@ -47,15 +47,15 @@ let all_outputs = {
 }
 in
 
-let version = "2.42" in
+let version = "2.43" in
 {
   name = "glibc",
   build_deps = [
     { file = "build.sh" } | Local,
     {
       # Downloadable from: https://ftp.gnu.org/gnu/glibc/
       url = "gs://minimal-staging-archives/glibc-%{version}.tar.xz",
-      sha256 = "d1775e32e4628e64ef930f435b67bb63af7599acb6be2b335b9f19f16509f17f"
+      sha256 = "d9c86c6b5dbddb43a3e08270c5844fc5177d19442cf5b8df4be7c07cd5fa3831"
     } | Source,
     # base
     bash,

@@ -6,7 +6,14 @@ case $(uname -m) in
   aarch64) MARCH="-march=armv8-a" ;;
   *)       MARCH="" ;;
 esac
-export CFLAGS="$MARCH -O2 -pipe -gno-record-gcc-switches -ffile-prefix-map=$(pwd)=/builddir"
+# -Wno-error=discarded-qualifiers: glibc 2.43's ISO C23 const-preserving
+# strchr/strstr/memchr return `const char *` for a `const char *` arg, which
+# libxcrypt's crypt-{gost,sm3}-yescrypt.c assign to a plain `char *` — tripping
+# libxcrypt's own configure-enabled -Werror. This package has a hand-written
+# build.sh (not the make stack), so the stacks/make/stack.ncl fleet lever can't
+# reach it; we downgrade only that one warning here, landing after libxcrypt's
+# -Werror on the compile line so the later flag wins. Same class as #238.
+export CFLAGS="$MARCH -O2 -pipe -gno-record-gcc-switches -ffile-prefix-map=$(pwd)=/builddir -Wno-error=discarded-qualifiers"
 export LDFLAGS="-Wl,--build-id=none"
 export CXXFLAGS="${CFLAGS}"
 

@@ -13,6 +13,20 @@ export CFLAGS="$MARCH -O2 -pipe -gno-record-gcc-switches -ffile-prefix-map=$(pwd
 export LDFLAGS="-Wl,--build-id=none"
 export CXXFLAGS="$CFLAGS"
 
+# SCIP (FetchContent'd by or-tools under USE_SCIP=ON) bundles tinycthread, a C11
+# <threads.h> shim that does `#define once_flag pthread_once_t`. glibc 2.43
+# surfaces its native once_flag/call_once into SCIP's translation unit, so that
+# macro corrupts glibc's `typedef __once_flag once_flag;` into a redefinition of
+# pthread_once_t -> "conflicting types" FTBFS. or-tools hard-FORCEs SCIP's
+# TPI=tny in its bundled cmake, so a top-level -DTPI=... can't override it; patch
+# the source to use SCIP's OpenMP task interface instead (drops tinycthread,
+# keeps SCIP parallel + THREADSAFE — SCIP auto-forces THREADSAFE on for any
+# non-"none" TPI). libgomp is present from our gcc build. Fails fast at configure
+# if OpenMP is somehow absent. glibc-2.43 toolchain-bump fallout, #238.
+sed -i 's|set(TPI "tny" CACHE STRING "Scip param" FORCE)|set(TPI "omp" CACHE STRING "Scip param" FORCE)|' ../cmake/dependencies/CMakeLists.txt
+grep -q 'set(TPI "omp"' ../cmake/dependencies/CMakeLists.txt \
+  || { echo "ERROR: SCIP TPI patch did not apply — or-tools cmake/dependencies/CMakeLists.txt changed upstream"; exit 1; }
+
 cmake -G Ninja \
   -DCMAKE_INSTALL_PREFIX=/usr \
   -DCMAKE_INSTALL_LIBDIR=/usr/lib \

@@ -9,7 +9,11 @@ case $(uname -m) in
   aarch64) MARCH="-march=armv8-a" ;;
   *)       MARCH="" ;;
 esac
-export CFLAGS="$MARCH -O2 -pipe -gno-record-gcc-switches -ffile-prefix-map=$(pwd)=/builddir"
+# -Wno-error=discarded-qualifiers: glibc 2.43's ISO C23 const-preserving bsearch
+# returns const for a const arg; strace's ioctl.c assigns it to a plain pointer
+# (iop = bsearch(..., ioctlent, ...)) under its default-on -Werror. Lands after
+# strace's -Werror on the compile line so the later flag wins. glibc-2.43 class, #238.
+export CFLAGS="$MARCH -O2 -pipe -gno-record-gcc-switches -ffile-prefix-map=$(pwd)=/builddir -Wno-error=discarded-qualifiers"
 export LDFLAGS="-Wl,--build-id=none"
 export CXXFLAGS="${CFLAGS}"
 

@@ -6,7 +6,22 @@ stack {
   build_env_vars = {
     CC = "gcc",
     CXX = "g++",
-    CFLAGS = "-O2 -pipe -gno-record-gcc-switches",
+    # glibc 2.43 implements ISO C23 const-preserving string macros: strchr,
+    # strrchr, strstr, memchr, etc. now return a `const char *` for a
+    # `const char *` argument. Pre-C23 code that assigns the result to a plain
+    # `char *` then trips -Werror=discarded-qualifiers and FTBFS. This is an
+    # ecosystem-wide wave (openssl, libxcrypt, grub, ...), not a one-off, so
+    # downgrade ONLY that one warning fleet-wide for every make/autotools
+    # build. It lands after each package's own -Werror on the compile line, so
+    # the later flag wins. This is DURABLE, not interim: a gcc-16 bump only
+    # fixes gcc's OWN source (its libgomp), so it retires packages/gcc/build.sh
+    # — it does NOT help the rest of the fleet, which still trips the same break
+    # under any gcc against glibc 2.43. This lever stays until either the
+    # ecosystem adopts C23-compatible source or we move it to -std=gnu17 (which
+    # restores the C17 prototypes so strchr returns `char *` — no warning at
+    # all, but a broader language-standard change).
+    # Ref: https://lists.gnu.org/archive/html/info-gnu/2026-01/msg00005.html
+    CFLAGS = "-O2 -pipe -gno-record-gcc-switches -Wno-error=discarded-qualifiers",
   },
 
   build_cmds_cmd = [