Build: Out-of-tree build system with separate build directory

- Build in build/ directory instead of source tree
- Main binary (utun) copied to project root
- Tests run from build/tests/ with config files copied there
- Test output redirected to build/tests/logs/*.log files
- Console shows only [PASS]/[FAIL]/[SKIP] status
- Incremental build works correctly
- make check runs all tests with summary

Changes:
- New root Makefile as wrapper for out-of-tree build
- Updated Makefile.am files for lib, src, tests
- Added tinycrypt-objects target for test dependencies
- Tests no longer clutter project root

src/Makefile.am

@@ -61,32 +61,70 @@ else
 utun_LDADD = $(utun_CORE_LDADD)
 endif
 
-# Object directory for shadow build artifacts
-OBJDIR = $(top_builddir)/.objs/src
-TINYCRYPT_OBJDIR = $(top_builddir)/.objs/tinycrypt
+# TinyCrypt object files (for tests that need them)
+TINYCRYPT_SRCDIR = $(top_srcdir)/tinycrypt/lib/source
 
-# After building, move object files to shadow directory
-all-local: shadow-objects
+TINYCRYPT_OBJS = \
+	utun-aes_encrypt.o \
+	utun-aes_decrypt.o \
+	utun-ccm_mode.o \
+	utun-cmac_mode.o \
+	utun-ctr_mode.o \
+	utun-ecc.o \
+	utun-ecc_dh.o \
+	utun-ecc_dsa.o \
+	utun-sha256.o \
+	utun-ecc_platform_specific.o \
+	utun-utils.o
 
-shadow-objects: utun$(EXEEXT)
-	@$(MKDIR_P) $(OBJDIR) $(TINYCRYPT_OBJDIR)
-	@for obj in $(utun_OBJECTS); do \
-		if test -f "$$obj"; then \
-			case "$$obj" in \
-				*lib/source/*.o) \
-					base=$$(basename $$obj | sed 's/^utun-//'); \
-					mv -f "$$obj" $(TINYCRYPT_OBJDIR)/"$$base" 2>/dev/null || true; \
-					;; \
-				*) \
-					mv -f "$$obj" $(OBJDIR)/ 2>/dev/null || true; \
-					;; \
-			esac; \
-		fi; \
-	done
+# Rules to build TinyCrypt objects (for tests)
+TINYCRYPT_CFLAGS = -I$(top_srcdir)/tinycrypt/lib/include -I$(top_srcdir)/tinycrypt/lib/source
 
-# Clean shadow directories along with regular clean
+utun-aes_encrypt.o: $(TINYCRYPT_SRCDIR)/aes_encrypt.c
+	$(AM_V_CC)$(COMPILE) $(TINYCRYPT_CFLAGS) -c -o $@ $<
+
+utun-aes_decrypt.o: $(TINYCRYPT_SRCDIR)/aes_decrypt.c
+	$(AM_V_CC)$(COMPILE) $(TINYCRYPT_CFLAGS) -c -o $@ $<
+
+utun-ccm_mode.o: $(TINYCRYPT_SRCDIR)/ccm_mode.c
+	$(AM_V_CC)$(COMPILE) $(TINYCRYPT_CFLAGS) -c -o $@ $<
+
+utun-cmac_mode.o: $(TINYCRYPT_SRCDIR)/cmac_mode.c
+	$(AM_V_CC)$(COMPILE) $(TINYCRYPT_CFLAGS) -c -o $@ $<
+
+utun-ctr_mode.o: $(TINYCRYPT_SRCDIR)/ctr_mode.c
+	$(AM_V_CC)$(COMPILE) $(TINYCRYPT_CFLAGS) -c -o $@ $<
+
+utun-ecc.o: $(TINYCRYPT_SRCDIR)/ecc.c
+	$(AM_V_CC)$(COMPILE) $(TINYCRYPT_CFLAGS) -c -o $@ $<
+
+utun-ecc_dh.o: $(TINYCRYPT_SRCDIR)/ecc_dh.c
+	$(AM_V_CC)$(COMPILE) $(TINYCRYPT_CFLAGS) -c -o $@ $<
+
+utun-ecc_dsa.o: $(TINYCRYPT_SRCDIR)/ecc_dsa.c
+	$(AM_V_CC)$(COMPILE) $(TINYCRYPT_CFLAGS) -c -o $@ $<
+
+utun-sha256.o: $(TINYCRYPT_SRCDIR)/sha256.c
+	$(AM_V_CC)$(COMPILE) $(TINYCRYPT_CFLAGS) -c -o $@ $<
+
+utun-ecc_platform_specific.o: $(TINYCRYPT_SRCDIR)/ecc_platform_specific.c
+	$(AM_V_CC)$(COMPILE) $(TINYCRYPT_CFLAGS) -c -o $@ $<
+
+utun-utils.o: $(TINYCRYPT_SRCDIR)/utils.c
+	$(AM_V_CC)$(COMPILE) $(TINYCRYPT_CFLAGS) -c -o $@ $<
+
+# Build TinyCrypt objects for tests (convenience target)
+tinycrypt-objects: $(TINYCRYPT_OBJS)
+
+# Copy binary to project root after building
+all-local: copy-to-root
+
+copy-to-root: utun$(EXEEXT)
+	@cp -f utun$(EXEEXT) $(top_srcdir)/
+
+# Clean
 clean-local:
-	-rm -rf $(OBJDIR) $(TINYCRYPT_OBJDIR)
+	@true
 
 # Install directories
 install-exec-hook: