Use depends for Linux daemon builds

contrib/build-linux.sh

@@ -4,22 +4,36 @@ set -euo pipefail
 ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
 JOBS="${JOBS:-1}"
 MODE="${MODE:-daemon}"
+HOST="${HOST:-$("$ROOT/depends/config.guess")}"
+PREFIX="$ROOT/depends/$HOST"
+BASE_CONFIG="$PREFIX/share/config.site"
+
+require_path() {
+  if [[ ! -e "$1" ]]; then
+    echo "Missing required path: $1" >&2
+    exit 1
+  fi
+}
 
 cd "$ROOT"
 
-if [[ ! -f configure ]]; then
-  ./autogen.sh
-fi
-
 case "$MODE" in
   daemon)
-    ./configure \
+    echo "Building native daemon depends for $HOST..."
+    make -C depends HOST="$HOST" NO_QT=1 -j"$JOBS"
+    require_path "$BASE_CONFIG"
+
+    if [[ ! -f configure ]]; then
+      ./autogen.sh
+    fi
+
+    echo "Configuring Linux daemon build..."
+    CONFIG_SITE="$BASE_CONFIG" ./configure \
       --without-gui \
       --disable-tests \
       --disable-bench \
       --disable-zmq \
       --with-miniupnpc=no \
-      --with-incompatible-bdb \
       CXXFLAGS="${CXXFLAGS:--O0 -g0 --param ggc-min-expand=1 --param ggc-min-heapsize=32768}"
     ;;
   wallet)

doc/build-menu.md

@@ -38,6 +38,10 @@ packages. If they are missing, it asks before adding a standard
 `/etc/apt/sources.list.d/agrarian-ubuntu.sources` file for the host
 architecture.
 
+The Linux daemon option uses the deterministic native `depends/` build with Qt
+disabled, so Berkeley DB and other core libraries are built inside the checkout
+instead of being required as Ubuntu system development packages.
+
 Defaults
 --------
 

doc/build-ubuntu-24.md

@@ -30,26 +30,17 @@ For a headless Qt wallet smoke test, also install:
     sudo apt-get install -y \
       xvfb
 
-Daemon-only build
------------------
+Daemon build
+------------
 
-For the pool daemon, the GUI, tests, bench, ZMQ, and UPnP can be disabled:
-
-    ./autogen.sh
-    ./configure \
-      --without-gui \
-      --disable-tests \
-      --disable-bench \
-      --disable-zmq \
-      --with-miniupnpc=no \
-      --with-incompatible-bdb \
-      CXXFLAGS="-O0 -g0 --param ggc-min-expand=1 --param ggc-min-heapsize=32768"
-    make -j1
-
-The daemon helper runs the same path:
+For the daemon and CLI tools, use:
 
     JOBS=1 ./contrib/build-linux.sh
 
+The daemon helper builds/restores the native deterministic depends prefix first
+with Qt disabled. Berkeley DB, OpenSSL, Boost, libevent, GMP, and supporting
+libraries come from `depends/`, not from Ubuntu system headers.
+
 Qt wallet build
 ---------------