fix_ci_error

Makefile

@@ -68,9 +68,9 @@ prerequisite:
 		python -c "from setuptools import setup, Extension; from Cython.Build import cythonize; import numpy; extensions = [Extension('qlib.data._libs.rolling', ['qlib/data/_libs/rolling.pyx'], language='c++', include_dirs=[numpy.get_include()]), Extension('qlib.data._libs.expanding', ['qlib/data/_libs/expanding.pyx'], language='c++', include_dirs=[numpy.get_include()])]; setup(ext_modules=cythonize(extensions, language_level='3'), script_args=['build_ext', '--inplace'])"; \
 	fi
 
-	ifeq ($(IS_WINDOWS),true)
-		python -m pip install pywinpty --only-binary=:all:
-	endif
+	@if [ "$(IS_WINDOWS)" = "true" ]; then \
+		python -m pip install pywinpty --only-binary=:all:; \
+	fi
 
 # Install the package in editable mode.
 dependencies: