Fixed:

- Path dependencies now work correctly: `dcr add` stores them as `{ path =
"./..." }` tables, `is_registry_dep` properly distinguishes registry strings
from path/git strings, and `deps/mod.rs` resolves both table-form and
legacy string-form path dependencies
- Registry dependency paths no longer hardcoded to `project_root/dcr-index`;
now use `package_root_from_registry_info()` which resolves relative to the
registry cache root (`~/.dcr/`)
- Registry dependencies are now actually built: `build_project_at()` is
called when `include_dir` or `lib_dir` is missing

Added:

- `SIGINT`/`Ctrl+C` handler via `ctrlc` crate — `dcr build` now checks
`BUILD_INTERRUPTED` flag at key points and aborts cleanly
- `utils/build.rs` — extracted shared utilities: `parse_version_info`,
`normalize_target_os`, `resolve_compiler`, `primary_language`,
`resolve_pkg_config_flags` and config helpers. Eliminates code duplication
between `cli/build.rs`, `cli/run.rs`, `cli/clean.rs`, `cli/gen.rs`
- `utils/fs.rs::with_dir` — extracted common directory-scoped execution
- `run_command_sync_output` in `builder/common.rs` with global `OUTPUT_MUTEX`
— synchronized compiler output across all backends (unix_cc, gas, nasm, msvc)
- New helper functions in `deps/register.rs`: `get_registry_cache_root`,
`package_root_from_registry_info`, `registry_include_dir`, `registry_lib_dir`,
`path_from_string_dep`
- Unit tests for `register.rs` (`is_registry_dep`, `package_root_from_registry_info`),
`deps/mod.rs` (`path_dep_path`, `push_default_lib_dirs`),
`utils/build.rs` (`normalize_target_os`, `parse_version_info`)

Removed:

- Removed unused dependencies `indicatif` and `console` from `Cargo.toml`

src/core/builder/common.rs

@@ -1,5 +1,9 @@
 use std::fs;
 use std::path::{Path, PathBuf};
+use std::process::Command;
+use std::sync::{Mutex, OnceLock};
+
+static OUTPUT_MUTEX: OnceLock<Mutex<()>> = OnceLock::new();
 
 pub fn collect_sources(
     roots: &[PathBuf],
@@ -196,6 +200,22 @@ where
     Ok(())
 }
 
+pub fn run_command_sync_output(cmd: &mut Command) -> Result<(), String> {
+    let output = cmd.output().map_err(|err| format!("Build failed: {err}"))?;
+    let _guard = OUTPUT_MUTEX.get_or_init(|| Mutex::new(())).lock().unwrap();
+    if !output.stdout.is_empty() {
+        print!("{}", String::from_utf8_lossy(&output.stdout));
+    }
+    if !output.stderr.is_empty() {
+        eprint!("{}", String::from_utf8_lossy(&output.stderr));
+    }
+    if output.status.success() {
+        Ok(())
+    } else {
+        Err("Build failed".to_string())
+    }
+}
+
 pub fn normalize_source_path(path: &Path) -> String {
     if !path.is_absolute() {
         return path.to_string_lossy().to_string();