dcr Files

Added:

• build.kind = "efi" — UEFI PE32+ executable support. Links with -shared -nostdlib -Wl,-dll -Wl,--subsystem,10, output via efi_path() with .efi extension, rejected by dcr run.
• build.kind = "elf" — bare-metal ELF executable support. Uses elf_path() output path, rejected by dcr run, no extra linker flags.
• build.filename and build.extension in dcr.toml — complete control over the final artifact name without relying on package.name. Example: toml [build] filename = "KERNEL" extension = "EFI" Produces KERNEL.EFI (works for bin, staticlib, and sharedlib).
• Automatic injection of --target=<build.target> into compiler flags when build.target is set in dcr.toml. This greatly simplifies clang-based cross-compilation (especially for bare-metal targets like aarch64-none-elf).
• Bare-metal targets (containing none, -elf, eabi, baremetal) no longer receive DCR's internal default flags (-g, -Wall, -Wextra, -fno-omit-frame-pointer, -DDCR_DEBUG, etc.). Prevents unwanted sections (.comment, debug info, etc.) that break custom linker scripts when inherit = true.
• build.ldscript in dcr.toml — linker script path passed as -T <path> to the linker. Essential for bare-metal/embedded/freestanding targets.
• dcr build --verbose — prints compiler/linker command lines (also works with DCR_DEBUG env var).
• dcr add <name> without a source argument — if a registry is configured, DCR looks up the package by name and adds it as a version dependency.

Fixed:

• build.target declared in dcr.toml is now correctly used as the default target even when --target is not passed on the command line (previously the host target was always forced for config resolution).
• dcr run with --target or build.target now correctly finds the binary in the arch-specific target directory.
• dcr run checks profile-specific build.{profile}.kind before rejecting library builds (previously only checked build.kind).
• dcr clean now reads build.target from dcr.toml when no --target flag is given.
• Linux: target directory is now consistent — target/<arch>-unknown-linux-gnu/<profile>/ (no stale target/<profile>/).
• dcr.lock is now populated with all resolved dependencies (registry, path, git) instead of being always empty.
• Git dependencies are now properly recognized and recorded in dcr.lock.
• is_registry_dep correctly identifies version-based registry dependency tables ({ version = "..." }) and rejects tables with unknown keys.
• dcr test accepts --debug/--release flags (defaults to debug profile instead of always release).
• Build fingerprint cache (build_cache_path) now includes target_dir — different targets no longer share a single cache entry.
• object_path no longer hardcodes the src/ prefix — works correctly with custom build.roots (e.g. roots = ["lib"]).
• dcr update now generates .exe candidates for all Windows targets, not just x86_64-pc-windows-msvc.
• Compiler existence is verified before starting the build (clear error if compiler is not found in PATH).
• Consolidated duplicate OUTPUT_MUTEX definitions — MSVC backend now uses the shared mutex from common.rs.
• Registry cache root directory is created if missing (prevents cryptic errors when ~/.dcr/ does not exist).

Changed:

• openssl dependency is now conditional (cfg(not(windows))) — no longer pulled in on Windows, fixing Windows CI builds that lack Perl Locale::Maketext::Simple. On Linux (including musl cross-compilation) the vendored OpenSSL build is unchanged.