Support .exe file extension in Makefile on MSYS2 (#15123)

`.build/crystal` already adds the `.exe` file extension in `Makefile` when run on MSYS2. This PR does the same to the spec executables so that running `make std_spec` twice will only build the executable once.

Makefile

@@ -68,10 +68,10 @@ CXXFLAGS += $(if $(debug),-g -O0)
 
 # MSYS2 support (native Windows should use `Makefile.win` instead)
 ifeq ($(OS),Windows_NT)
-  CRYSTAL_BIN := crystal.exe
+  EXE := .exe
   WINDOWS := 1
 else
-  CRYSTAL_BIN := crystal
+  EXE :=
   WINDOWS :=
 endif
 
@@ -112,28 +112,28 @@ test: spec ## Run tests
 spec: std_spec primitives_spec compiler_spec
 
 .PHONY: std_spec
-std_spec: $(O)/std_spec ## Run standard library specs
-	$(O)/std_spec $(SPEC_FLAGS)
+std_spec: $(O)/std_spec$(EXE) ## Run standard library specs
+	$(O)/std_spec$(EXE) $(SPEC_FLAGS)
 
 .PHONY: compiler_spec
-compiler_spec: $(O)/compiler_spec ## Run compiler specs
-	$(O)/compiler_spec $(SPEC_FLAGS)
+compiler_spec: $(O)/compiler_spec$(EXE) ## Run compiler specs
+	$(O)/compiler_spec$(EXE) $(SPEC_FLAGS)
 
 .PHONY: primitives_spec
-primitives_spec: $(O)/primitives_spec ## Run primitives specs
-	$(O)/primitives_spec $(SPEC_FLAGS)
+primitives_spec: $(O)/primitives_spec$(EXE) ## Run primitives specs
+	$(O)/primitives_spec$(EXE) $(SPEC_FLAGS)
 
 .PHONY: interpreter_spec
-interpreter_spec: $(O)/interpreter_spec ## Run interpreter specs
-	$(O)/interpreter_spec $(SPEC_FLAGS)
+interpreter_spec: $(O)/interpreter_spec$(EXE) ## Run interpreter specs
+	$(O)/interpreter_spec$(EXE) $(SPEC_FLAGS)
 
 .PHONY: smoke_test
 smoke_test: ## Build specs as a smoke test
-smoke_test: $(O)/std_spec $(O)/compiler_spec $(O)/$(CRYSTAL_BIN)
+smoke_test: $(O)/std_spec$(EXE) $(O)/compiler_spec$(EXE) $(O)/$(CRYSTAL)$(EXE)
 
 .PHONY: all_spec
-all_spec: $(O)/all_spec ## Run all specs (note: this builds a huge program; `test` recipe builds individual binaries and is recommended for reduced resource usage)
-	$(O)/all_spec $(SPEC_FLAGS)
+all_spec: $(O)/all_spec$(EXE) ## Run all specs (note: this builds a huge program; `test` recipe builds individual binaries and is recommended for reduced resource usage)
+	$(O)/all_spec$(EXE) $(SPEC_FLAGS)
 
 .PHONY: samples
 samples: ## Build example programs
@@ -146,7 +146,7 @@ docs: ## Generate standard library documentation
 	cp -av doc/ docs/
 
 .PHONY: crystal
-crystal: $(O)/$(CRYSTAL_BIN) ## Build the compiler
+crystal: $(O)/$(CRYSTAL)$(EXE) ## Build the compiler
 
 .PHONY: deps llvm_ext
 deps: $(DEPS) ## Build dependencies
@@ -161,9 +161,9 @@ generate_data: ## Run generator scripts for Unicode, SSL config, ...
 	$(MAKE) -B -f scripts/generate_data.mk
 
 .PHONY: install
-install: $(O)/$(CRYSTAL_BIN) man/crystal.1.gz ## Install the compiler at DESTDIR
+install: $(O)/$(CRYSTAL)$(EXE) man/crystal.1.gz ## Install the compiler at DESTDIR
 	$(INSTALL) -d -m 0755 "$(BINDIR)/"
-	$(INSTALL) -m 0755 "$(O)/$(CRYSTAL_BIN)" "$(BINDIR)/$(CRYSTAL_BIN)"
+	$(INSTALL) -m 0755 "$(O)/$(CRYSTAL)$(EXE)" "$(BINDIR)/$(CRYSTAL)$(EXE)"
 
 	$(INSTALL) -d -m 0755 $(DATADIR)
 	cp -av src "$(DATADIR)/src"
@@ -183,14 +183,14 @@ install: $(O)/$(CRYSTAL_BIN) man/crystal.1.gz ## Install the compiler at DESTDIR
 
 ifeq ($(WINDOWS),1)
 .PHONY: install_dlls
-install_dlls: $(O)/$(CRYSTAL_BIN) ## Install the compiler's dependent DLLs at DESTDIR (Windows only)
+install_dlls: $(O)/$(CRYSTAL)$(EXE) ## Install the compiler's dependent DLLs at DESTDIR (Windows only)
 	$(INSTALL) -d -m 0755 "$(BINDIR)/"
-	@ldd $(O)/$(CRYSTAL_BIN) | grep -iv ' => /c/windows/system32' | sed 's/.* => //; s/ (.*//' | xargs -t -i $(INSTALL) -m 0755 '{}' "$(BINDIR)/"
+	@ldd $(O)/$(CRYSTAL)$(EXE) | grep -iv ' => /c/windows/system32' | sed 's/.* => //; s/ (.*//' | xargs -t -i $(INSTALL) -m 0755 '{}' "$(BINDIR)/"
 endif
 
 .PHONY: uninstall
 uninstall: ## Uninstall the compiler from DESTDIR
-	rm -f "$(BINDIR)/$(CRYSTAL_BIN)"
+	rm -f "$(BINDIR)/$(CRYSTAL)$(EXE)"
 
 	rm -rf "$(DATADIR)/src"
 
@@ -212,31 +212,31 @@ uninstall_docs: ## Uninstall docs from DESTDIR
 	rm -rf "$(DATADIR)/docs"
 	rm -rf "$(DATADIR)/examples"
 
-$(O)/all_spec: $(DEPS) $(SOURCES) $(SPEC_SOURCES)
+$(O)/all_spec$(EXE): $(DEPS) $(SOURCES) $(SPEC_SOURCES)
 	$(call check_llvm_config)
 	@mkdir -p $(O)
 	$(EXPORT_CC) $(EXPORTS) ./bin/crystal build $(FLAGS) $(SPEC_WARNINGS_OFF) -o $@ spec/all_spec.cr
 
-$(O)/std_spec: $(DEPS) $(SOURCES) $(SPEC_SOURCES)
+$(O)/std_spec$(EXE): $(DEPS) $(SOURCES) $(SPEC_SOURCES)
 	$(call check_llvm_config)
 	@mkdir -p $(O)
 	$(EXPORT_CC) ./bin/crystal build $(FLAGS) $(SPEC_WARNINGS_OFF) -o $@ spec/std_spec.cr
 
-$(O)/compiler_spec: $(DEPS) $(SOURCES) $(SPEC_SOURCES)
+$(O)/compiler_spec$(EXE): $(DEPS) $(SOURCES) $(SPEC_SOURCES)
 	$(call check_llvm_config)
 	@mkdir -p $(O)
 	$(EXPORT_CC) $(EXPORTS) ./bin/crystal build $(FLAGS) $(SPEC_WARNINGS_OFF) -o $@ spec/compiler_spec.cr --release
 
-$(O)/primitives_spec: $(O)/$(CRYSTAL_BIN) $(DEPS) $(SOURCES) $(SPEC_SOURCES)
+$(O)/primitives_spec$(EXE): $(O)/$(CRYSTAL)$(EXE) $(DEPS) $(SOURCES) $(SPEC_SOURCES)
 	@mkdir -p $(O)
 	$(EXPORT_CC) ./bin/crystal build $(FLAGS) $(SPEC_WARNINGS_OFF) -o $@ spec/primitives_spec.cr
 
-$(O)/interpreter_spec: $(DEPS) $(SOURCES) $(SPEC_SOURCES)
+$(O)/interpreter_spec$(EXE): $(DEPS) $(SOURCES) $(SPEC_SOURCES)
 	$(eval interpreter=1)
 	@mkdir -p $(O)
 	$(EXPORT_CC) ./bin/crystal build $(FLAGS) $(SPEC_WARNINGS_OFF) -o $@ spec/compiler/interpreter_spec.cr
 
-$(O)/$(CRYSTAL_BIN): $(DEPS) $(SOURCES)
+$(O)/$(CRYSTAL)$(EXE): $(DEPS) $(SOURCES)
 	$(call check_llvm_config)
 	@mkdir -p $(O)
 	@# NOTE: USE_PCRE1 is only used for testing compatibility with legacy environments that don't provide libpcre2.