feat(llama.cpp): add turboquant support

This PR adds patchset from the great work of @TheTom in
https://github.com/TheTom/llama-cpp-turboquant and creates a pipeline
that updates the patches against upstream automatically.

It also creates necessary scaffolding for doing this with other patches
sources.

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

scripts/patch_utils/apply_patches.sh

@@ -0,0 +1,109 @@
+#!/bin/bash
+# apply_patches.sh — Generic patch fetcher and applier for any backend.
+#
+# Usage: ./apply_patches.sh <source-dir> <target-dir>
+#
+#   <source-dir>  Directory containing a patches/ folder (with optional sources.yaml)
+#   <target-dir>  The cloned upstream repo to patch (e.g., llama.cpp/)
+#
+# Behavior (idempotent):
+#   1. If patches/sources.yaml exists and yq is available, for each source:
+#      - If patches/<name>/ already has .patch files: skip fetching (vendored)
+#      - Otherwise: clone the fork, auto-detect the fork base via merge-base
+#        with the upstream repo, and generate patches
+#   2. Apply all patches from source subdirectories (alphabetical), then top-level .patch files
+#   3. Fails fast on any patch application error
+
+set -e
+
+apply_patches() {
+    local SOURCE_DIR="$(cd "$1" && pwd)"
+    local TARGET_DIR="$2"
+    local PATCHES_DIR="$SOURCE_DIR/patches"
+
+    if [ ! -d "$PATCHES_DIR" ]; then
+        return 0
+    fi
+
+    # Phase 1: Generate missing patches from fork sources
+    if [ -f "$PATCHES_DIR/sources.yaml" ] && command -v yq &>/dev/null; then
+        local SOURCE_COUNT
+        SOURCE_COUNT=$(yq '.sources | length' "$PATCHES_DIR/sources.yaml")
+
+        for i in $(seq 0 $((SOURCE_COUNT - 1))); do
+            local NAME REPO BRANCH UPSTREAM_REPO
+            NAME=$(yq ".sources[$i].name" "$PATCHES_DIR/sources.yaml")
+            REPO=$(yq ".sources[$i].repo" "$PATCHES_DIR/sources.yaml")
+            BRANCH=$(yq ".sources[$i].branch" "$PATCHES_DIR/sources.yaml")
+            UPSTREAM_REPO=$(yq ".sources[$i].upstream_repo" "$PATCHES_DIR/sources.yaml")
+
+            local SOURCE_PATCH_DIR="$PATCHES_DIR/$NAME"
+            local EXISTING
+            EXISTING=$(ls "$SOURCE_PATCH_DIR"/*.patch 2>/dev/null | wc -l)
+
+            if [ "$EXISTING" -gt 0 ]; then
+                echo "Patches [$NAME]: $EXISTING patches already present — skipping fetch."
+            else
+                echo "Patches [$NAME]: fetching from $REPO ($BRANCH)"
+
+                local TMPDIR
+                TMPDIR=$(mktemp -d)
+
+                if git clone --single-branch -b "$BRANCH" "$REPO" "$TMPDIR/fork" 2>&1; then
+                    cd "$TMPDIR/fork"
+
+                    # Auto-detect fork base: merge-base between fork and upstream
+                    git remote add upstream "$UPSTREAM_REPO"
+                    git fetch upstream 2>&1
+
+                    local FORK_BASE
+                    FORK_BASE=$(git merge-base HEAD upstream/master 2>/dev/null || \
+                                git merge-base HEAD upstream/main 2>/dev/null || echo "")
+
+                    if [ -z "$FORK_BASE" ]; then
+                        echo "WARNING: Could not find merge-base with upstream — skipping source '$NAME'"
+                        cd "$SOURCE_DIR"
+                        rm -rf "$TMPDIR"
+                        continue
+                    fi
+
+                    local PATCH_COUNT
+                    PATCH_COUNT=$(git rev-list --count "$FORK_BASE"..HEAD 2>/dev/null || echo "0")
+                    echo "  Fork base: ${FORK_BASE:0:12} ($PATCH_COUNT commits to extract)"
+
+                    if [ "$PATCH_COUNT" -gt 0 ]; then
+                        mkdir -p "$SOURCE_PATCH_DIR"
+                        git format-patch "$FORK_BASE"..HEAD -o "$SOURCE_PATCH_DIR/" >/dev/null 2>&1
+                        echo "  Generated $PATCH_COUNT patches in patches/$NAME/"
+                    fi
+                    cd "$SOURCE_DIR"
+                else
+                    echo "WARNING: Failed to clone $REPO — skipping source '$NAME'"
+                fi
+
+                rm -rf "$TMPDIR"
+            fi
+        done
+    elif [ -f "$PATCHES_DIR/sources.yaml" ]; then
+        echo "WARNING: yq not found — skipping source-based patch generation."
+    fi
+
+    # Phase 2: Apply patches (subdirectories first, then top-level)
+    for source_dir in $(find "$PATCHES_DIR" -mindepth 1 -maxdepth 1 -type d | sort); do
+        for p in $(ls "$source_dir"/*.patch 2>/dev/null | sort); do
+            echo "Applying: $(basename "$source_dir")/$(basename "$p")"
+            patch -d "$TARGET_DIR" -p1 < "$p" || { echo "FAILED: $p"; exit 1; }
+        done
+    done
+    for p in $(ls "$PATCHES_DIR"/*.patch 2>/dev/null | sort); do
+        echo "Applying: $(basename "$p")"
+        patch -d "$TARGET_DIR" -p1 < "$p" || { echo "FAILED: $p"; exit 1; }
+    done
+}
+
+# Run with arguments
+if [ $# -lt 2 ]; then
+    echo "Usage: $0 <source-dir> <target-dir>"
+    exit 1
+fi
+apply_patches "$1" "$2"