Require cmake-clang-v1 1.0.4 for Linux IPO linking.

Floor ensure-toolchain at 1.0.4 (libxml2 + clang.cfg -fuse-ld=lld) and
prepend pack lib/ to LD_LIBRARY_PATH when activating the toolchain.

Co-authored-by: Cursor <cursoragent@cursor.com>

docs/LOCAL_CODEGEN_SDK.md

@@ -41,8 +41,8 @@ with host-native `curl` + `tar`/`unzip` when possible — so Microsoft Store
 Python AppData redirection cannot hide cmake. Offline zips unpack to the same
 path. A legacy `%LOCALAPPDATA%/psxrecomp/…` cache is migrated automatically.
 Override with `RETCOMM_TOOLCHAIN_DIR`. Require a floor version via
-`RETCOMM_TOOLCHAIN_MIN_VERSION` / `ensure-toolchain --min-version` (Windows
-defaults to `1.0.3` for bundled zlib). Generate/rebuild still need Python 3
+`RETCOMM_TOOLCHAIN_MIN_VERSION` / `ensure-toolchain --min-version` (defaults to
+`1.0.4` for Linux LTO deps + Windows zlib). Generate/rebuild still need Python 3
 for `psxrecomp_cli.py`.
 
 ## Commands

host/psxrecomp_codegen_host.c

@@ -588,6 +588,23 @@ static void activate_toolchain_path(void) {
             if (pref[0])
                 setenv("CMAKE_PREFIX_PATH", pref, 1);
         }
+        /* Linux packs 1.0.4+: bundled libxml2.so.2 for lld / thin LTO. */
+        {
+            char libdir[1500];
+            if (join_path(libdir, sizeof(libdir), pack_root, "lib") &&
+                path_is_dir(libdir)) {
+                const char* prev = getenv("LD_LIBRARY_PATH");
+                char llp[8192];
+                if (prev && prev[0] && !strstr(prev, libdir))
+                    snprintf(llp, sizeof(llp), "%s:%s", libdir, prev);
+                else if (!prev || !prev[0])
+                    snprintf(llp, sizeof(llp), "%s", libdir);
+                else
+                    llp[0] = '\0';
+                if (llp[0])
+                    setenv("LD_LIBRARY_PATH", llp, 1);
+            }
+        }
 #endif
     }
 }
@@ -969,8 +986,9 @@ static int run_cli_posix(char* const argv[],
 /* ---- Host-native toolchain install (no Store Python AppData redirect) ---- */
 
 static const char* k_tc_repo = "TechnicallyComputers/retcomm-toolchains";
-/* Default floor for Windows zlib-in-pack; override with RETCOMM_TOOLCHAIN_MIN_VERSION. */
-static const char* k_tc_min_version_default = "1.0.3";
+/* Floor: Linux 1.0.4+ ships libxml2 + clang.cfg (-fuse-ld=lld) for IPO;
+ * Windows 1.0.3+ ships static zlib. Override with RETCOMM_TOOLCHAIN_MIN_VERSION. */
+static const char* k_tc_min_version_default = "1.0.4";
 
 static const char* toolchain_zip_asset_name(void) {
 #if defined(_WIN32)
@@ -986,13 +1004,7 @@ static const char* toolchain_min_version(void) {
     const char* env = getenv("RETCOMM_TOOLCHAIN_MIN_VERSION");
     if (env && env[0])
         return env;
-#if defined(_WIN32)
-    /* Windows packs from 1.0.3 ship static zlib for find_package(ZLIB). */
     return k_tc_min_version_default;
-#else
-    (void)k_tc_min_version_default;
-    return "";
-#endif
 }
 
 /* Parse leading dotted integers from a version / tag (optional leading 'v'). */

tools/toolchain_pack.py

@@ -184,10 +184,9 @@ def default_min_version() -> str:
     env = (os.environ.get("RETCOMM_TOOLCHAIN_MIN_VERSION") or "").strip()
     if env:
         return env
-    # Windows packs from 1.0.3 ship static zlib for find_package(ZLIB).
-    if sys_platform_is_windows():
-        return "1.0.3"
-    return ""
+    # 1.0.4+: Linux libxml2 + clang.cfg (-fuse-ld=lld) for IPO; Windows zlib
+    # since 1.0.3. Keep one floor so ensure-toolchain refreshes stale caches.
+    return "1.0.4"
 
 
 def pack_satisfies_min(root: Path, min_version: str = "") -> bool:
@@ -340,6 +339,15 @@ def activate_toolchain_bin(bin_dir: Path, log=None) -> None:
         os.environ["CMAKE_PREFIX_PATH"] = pack_s
     elif pack_s not in prev_prefix.split(os.pathsep):
         os.environ["CMAKE_PREFIX_PATH"] = pack_s + os.pathsep + prev_prefix
+    lib_dir = pack_root / "lib"
+    if lib_dir.is_dir() and not sys_platform_is_windows():
+        lib_s = str(lib_dir)
+        prev_llp = os.environ.get("LD_LIBRARY_PATH", "")
+        parts = prev_llp.split(os.pathsep) if prev_llp else []
+        if lib_s not in parts:
+            os.environ["LD_LIBRARY_PATH"] = lib_s + (
+                os.pathsep + prev_llp if prev_llp else ""
+            )
     for name, env_key in (
         ("clang", "CC"),
         ("clang++", "CXX"),
@@ -352,7 +360,6 @@ def activate_toolchain_bin(bin_dir: Path, log=None) -> None:
     if log:
         log(f"Using toolchain: {bin_dir}")
 
-
 def unpack_zip_to(zip_path: Path, dest: Path) -> Path:
     """Extract *zip_path* into *dest* (replaced) and return usable pack root."""
     if dest.exists():