fix release mode link path in final elf output

README.md

@@ -20,6 +20,7 @@ The application uses ALSA's default device, which is configured in `alsa.conf`.
 ### Prerequisites
 - Zig 0.15.1 (configured via mise)
 - Nix development environment configured for ALSA, and audio libraries
+- patchelf (for fixing RPATH in release builds): `nix-env -iA nixpkgs.patchelf`
 
 ### Vosk Model Download
 The application uses the Vosk small English model for speech recognition:
@@ -33,6 +34,20 @@ The application uses the Vosk small English model for speech recognition:
 2. Build application: `zig build`
 3. Run: `zig build run`
 
+### Release Builds and Portability
+
+When building in release mode (`-Doptimize=ReleaseSafe`), Zig embeds the full path to libvosk.so in the ELF NEEDED entries, making the binary non-portable. The build system automatically fixes this by running `fix_needed.sh` which uses `patchelf` to replace the full path with just the library name.
+
+**Automatic fix**: Just run `zig build -Doptimize=ReleaseSafe` - the NEEDED entries are fixed automatically.
+
+**Manual fix**: If needed, you can run `./fix_needed.sh [binary_path] [library_name]` manually.
+
+The script uses `patchelf` (via nix-shell if not installed) to replace entries like:
+- Before: `NEEDED: [/home/user/.cache/zig/.../libvosk.so]`
+- After: `NEEDED: [libvosk.so]`
+
+This makes the binary portable while using the existing RPATH (`$ORIGIN/../lib`) to find the library at runtime.
+
 ## Usage
 The application will:
 - Initialize audio capture from default microphone

build.zig

@@ -32,7 +32,7 @@ pub fn build(b: *std.Build) void {
     // Create the STT library
     const stt_lib = b.addLibrary(.{
         .name = "stt",
-        .linkage = .static,
+        // .linkage = .static,
         .root_module = b.createModule(.{
             .root_source_file = b.path("src/stt.zig"),
             .target = target,
@@ -73,7 +73,21 @@ pub fn build(b: *std.Build) void {
     exe.addLibraryPath(vosk_dep.path(""));
     exe.linkSystemLibrary("vosk");
 
-    b.installArtifact(exe);
+    const install_exe = b.addInstallArtifact(exe, .{});
+
+    // Fix NEEDED entries in release builds to make binary portable
+    if (optimize != .Debug) {
+        const script_path = b.pathFromRoot("fix_needed.sh");
+        const fix_needed = b.addSystemCommand(&.{script_path});
+        fix_needed.step.dependOn(&install_exe.step);
+        _ = fix_needed.captureStdOut();
+        b.getInstallStep().dependOn(&fix_needed.step);
+
+        const fix_step = b.step("fix-needed", "Fix NEEDED entries to make binary portable");
+        fix_step.dependOn(&fix_needed.step);
+    } else {
+        b.getInstallStep().dependOn(&install_exe.step);
+    }
 
     const run_step = b.step("run", "Run the app");
     const run_cmd = b.addRunArtifact(exe);

fix_needed.sh

@@ -0,0 +1,55 @@
+#!/bin/bash
+# Fix NEEDED entries in release builds
+# This script replaces full paths with just library names in NEEDED entries
+
+if [[ "$1" == "--help" || "$1" == "-h" ]]; then
+    echo "Usage: $0 [binary_path] [library_name]"
+    echo "  binary_path: Path to binary (default: script_dir/zig-out/bin/stt)"
+    echo "  library_name: Library to fix (default: libvosk.so)"
+    echo ""
+    echo "Example: $0 my_binary libfoo.so"
+    exit 0
+fi
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+BINARY="${1:-$SCRIPT_DIR/zig-out/bin/stt}"
+LIBRARY="${2:-libvosk.so}"
+
+if [ ! -f "$BINARY" ]; then
+    echo "Binary not found: $BINARY" >&2
+    exit 1
+fi
+
+echo "Fixing NEEDED entries for $BINARY..."
+
+# Get the current NEEDED entries
+if command -v readelf >/dev/null 2>&1; then
+    FULL_PATH=$(readelf --dynamic "$BINARY" | grep "NEEDED" | grep "$LIBRARY" | head -1 | sed 's/.*\[\(.*\)\]/\1/')
+elif command -v nix-shell >/dev/null 2>&1; then
+    echo "Using nix-shell to run readelf..."
+    FULL_PATH=$(nix-shell -p binutils --run "readelf --dynamic '$BINARY'" | grep "NEEDED" | grep "$LIBRARY" | head -1 | sed 's/.*\[\(.*\)\]/\1/')
+else
+    echo "Error: Neither readelf nor nix-shell found" >&2
+    echo "Install binutils or nix to check NEEDED entries" >&2
+    exit 1
+fi
+
+if [[ "$FULL_PATH" == *"/"* ]]; then
+    echo "Found full path: $FULL_PATH"
+    echo "Replacing with: $LIBRARY"
+
+    # Try patchelf directly, fall back to nix-shell
+    if command -v patchelf >/dev/null 2>&1; then
+        patchelf --replace-needed "$FULL_PATH" "$LIBRARY" "$BINARY"
+    elif command -v nix-shell >/dev/null 2>&1; then
+        echo "Using nix-shell to run patchelf..."
+        nix-shell -p patchelf --run "patchelf --replace-needed '$FULL_PATH' '$LIBRARY' '$BINARY'"
+    else
+        echo "Error: Neither patchelf nor nix-shell found" >&2
+        echo "Install patchelf or nix to fix NEEDED entries" >&2
+        exit 1
+    fi
+    echo "Fixed!"
+else
+    echo "No full path found, binary is already portable"
+fi