add bzip2 package (#28)

Static build of bzip2 1.0.8 (libbz2.a + bzlib.h) for use as a
vendored dependency in openpilot replay/cabana tools.

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

bzip2/build.sh

@@ -0,0 +1,45 @@
+#!/usr/bin/env bash
+set -e
+
+DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null && pwd)"
+cd "$DIR"
+
+VERSION="1.0.8"
+INSTALL_DIR="$DIR/bzip2/install"
+
+# Idempotent: skip if already built
+if [ -f "$INSTALL_DIR/lib/libbz2.a" ]; then
+  echo "bzip2 already present, skipping build."
+  exit 0
+fi
+
+NJOBS="$(nproc 2>/dev/null || sysctl -n hw.ncpu 2>/dev/null || echo 2)"
+
+# Download
+if [ ! -d "bzip2-src" ]; then
+  curl -L "https://sourceware.org/pub/bzip2/bzip2-${VERSION}.tar.gz" -o bzip2.tar.gz
+  mkdir -p bzip2-src
+  tar xzf bzip2.tar.gz -C bzip2-src --strip-components=1
+  rm bzip2.tar.gz
+fi
+
+# Build static library with -fPIC
+cd bzip2-src
+make -j"$NJOBS" libbz2.a CC="${CC:-cc}" CFLAGS="-Wall -Winline -O2 -fPIC -D_FILE_OFFSET_BITS=64"
+cd "$DIR"
+
+# Copy to package install dir
+rm -rf "$INSTALL_DIR"
+mkdir -p "$INSTALL_DIR"/{lib,include}
+
+# Library
+cp bzip2-src/libbz2.a "$INSTALL_DIR/lib/"
+
+# Headers
+cp bzip2-src/bzlib.h "$INSTALL_DIR/include/"
+
+# Clean up
+rm -rf bzip2-src
+
+echo "Installed bzip2 to $INSTALL_DIR"
+du -sh "$INSTALL_DIR"