feat: enhance cross-platform compilation support for polycrypt-rs v0.…

…4.5-beta.1

- Add musl target support for Linux cross-compilation
- Configure cargo for x86_64-unknown-linux-musl target
- Add build-linux target in Makefile for cross-compilation
- Add build-all target to compile for both native and Linux
- Update cleanup process to handle cross-compiled artifacts
- Improve platform-specific library handling
- Add CARGO_TARGET environment variable for Mac cross-compilation

BREAKING CHANGES:
- Requires musl-tools for Linux builds
- Changes build process to support cross-compilation

.cargo/config.toml

@@ -1 +1,2 @@
-
+[target.x86_64-unknown-linux-musl]
+linker = "x86_64-linux-musl-gcc" 

Makefile

@@ -26,10 +26,14 @@ else
     endif
     ifeq ($(UNAME_S),Darwin)
         LIB_EXT := dylib
+        # For cross-compilation from Mac
+        CARGO_TARGET_X86_64_UNKNOWN_LINUX_MUSL_LINKER := x86_64-linux-musl-gcc
+        export CARGO_TARGET_X86_64_UNKNOWN_LINUX_MUSL_LINKER
     endif
 endif
 
 LIB_NAME := libpolycrypt_rs.$(LIB_EXT)
+LINUX_LIB_NAME := libpolycrypt_rs.so
 
 # Colors
 CYAN := \033[36m
@@ -60,6 +64,24 @@ build:
 	@echo "$(GREEN)Library copied successfully.$(RESET_COLOR)"
 	@echo "$(DASH_LINE)"
 
+# Add cross-compilation target
+build-linux:
+	@echo "$(DASH_LINE)"
+	@echo "$(CYAN)Cross-compiling for Linux x86_64...$(RESET_COLOR)"
+	@echo "$(DASH_LINE)"
+	@rustup target add x86_64-unknown-linux-musl
+	@RUSTFLAGS="-C target-feature=-crt-static" $(CARGO) build --release --target x86_64-unknown-linux-musl
+	@echo "$(GREEN)Linux build completed successfully.$(RESET_COLOR)"
+	@echo "$(DASH_LINE)"
+	@echo "$(CYAN)Copying $(LINUX_LIB_NAME) to staging directory...$(RESET_COLOR)"
+	@mkdir -p $(RELEASE_DIR)/linux
+	@cp $(TARGET_DIR)/x86_64-unknown-linux-musl/release/$(LINUX_LIB_NAME) $(RELEASE_DIR)/linux/
+	@echo "$(GREEN)Linux library copied successfully.$(RESET_COLOR)"
+	@echo "$(DASH_LINE)"
+
+# Add a combined build target for both native and Linux
+build-all: build build-linux
+
 # Build for debug
 debug:
 	@echo "$(DASH_LINE)"
@@ -154,6 +176,7 @@ clean:
 	@rm -f $(GO_EXAMPLES_DIR)/polycrypt/libpolycrypt_rs.*
 	@rm -f $(GO_EXAMPLES_DIR)/polycrypt_ffi_go
 	@rm -f $(PYTHON_EXAMPLES_DIR)/polycrypt/libpolycrypt_rs.*
+	@rm -rf $(RELEASE_DIR)/linux
 	@echo "$(DASH_LINE)"
 	@echo "$(GREEN)Cleaning completed.$(RESET_COLOR)"
 	@echo "$(DASH_LINE)"