CMake: Relax check for Python 3.x support on Windows

Since the code is now ported to support Python 3.x on Windows, we can enable
building the Python-3.x version of the Python modules on Windows directly.

Not sure about the other platforms that the Python libxslt module supports, so
continue to require unistd.h and have F_GETFL support in fcntl.h on the other
platforms.

CMakeLists.txt

@@ -59,4 +59,5 @@
 if(LIBXSLT_WITH_PYTHON)
 	check_include_files(unistd.h HAVE_UNISTD_H)
 	check_symbol_exists(F_GETFL fcntl.h HAVE_F_GETFL)
+	if(WIN32 OR (HAVE_UNISTD_H AND HAVE_F_GETFL))
 		find_package(Python COMPONENTS Interpreter Development REQUIRED)
@@ -62,2 +63,8 @@
 		find_package(Python COMPONENTS Interpreter Development REQUIRED)
+	else()
+		find_package(Python2 COMPONENTS Interpreter Development REQUIRED)
+		add_library(Python::Python ALIAS Python2::Python)
+		set(Python_EXECUTABLE ${Python2_EXECUTABLE})
+		set(Python_SITEARCH ${Python2_SITEARCH})
+	endif()
 	#set(LIBXSLT_PYTHON_INSTALL_DIR ${Python_SITEARCH} CACHE PATH "Python bindings install directory")
@@ -63,6 +70,5 @@
 	#set(LIBXSLT_PYTHON_INSTALL_DIR ${Python_SITEARCH} CACHE PATH "Python bindings install directory")
-	set(LIBXSLT_PYTHON_INSTALL_DIR "${CMAKE_INSTALL_PREFIX}/python"
-	    CACHE PATH "Python bindings install directory")
+	set(LIBXSLT_PYTHON_INSTALL_DIR "${CMAKE_INSTALL_PREFIX}/python" CACHE PATH "Python bindings install directory")
 endif()
 
 if(LIBXSLT_WITH_THREADS)