Merge pull request '[libxml2]Add the libxml2 compilation operation process' (#3) from dev_zjl into dev

Reviewed-on: #3

README.md

@@ -11,3 +11,40 @@
 
 ## push 
 	git push origin dev_xxx -u
+
+
+
+## libxml2 record
+
+1. Use the autogen.sh script to generate makefile-related files.
+		autogen.sh
+2. Use `make` to execute the `makefile`
+		make
+	
+### Command operation principle
+#### .in file - "Template file" 
+1. Makefile.in: A template for Makefile. It is filled with placeholder variables such as @srcdir@, @CC@, @prefix@, etc. Configure replaces these variables with actual values, outputting a directly usable Makefile.
+2. config.h.in: A header file template. The configure script will generate config.h based on the detection results, which defines macros such as #define HAVE_STDLIB_H 1 for use in the source code.
+3. Why is it called .in? It stands for input template, waiting to be filled by configure.
+#### .m4 file - "Macro definition file" 
+1. m4 is an ancient macro processing language used by Autoconf to extend configure.ac.
+2. aclocal.m4: Generated by aclocal, it contains macros written by the project itself and macros installed by the system (such as macros for detecting a specific library), intended for use by autoconf.
+3. pkg.m4: This is a macro file provided by the pkg-config tool, which defines macros such as PKG_CHECK_MODULES, intended for conveniently detecting dependent libraries in configure.ac. Your script checks for its existence to ensure that the project can correctly detect dependencies.
+4. Other .m4 files: They are usually stored in /usr/share/aclocal and are detection macros provided by various third-party libraries.
+
+	Handwritten files: 
+	configure.ac (configuration requirements) 
+	Makefile.am (prototype of build rules) 
+	... source code ..
+	 ↓ Run autogen.sh (i.e., the script you analyzed)
+	Generated files: 
+	configure (executable configuration script), 
+	Makefile.in (Makefile template), 
+	aclocal.m4 (macro package), 
+	config.h.in (header file template)
+	 ↓ Run ./configure
+	Generated files: Makefile (final usable Makefile), 
+	config.h (final header file), 
+	config.status (configuration status script)
+
+Reference: https://chat.deepseek.com/share/yuz6k3q75v5qqop8h3