mysql不同linux下的安装路径不大相同，直接中包括，不同的版本下编译比较麻烦,装mysql也N种方法，还有x86和x64版本同时装的，搞得很混乱，参考了一下别人的检测做法,目前发现两种:

1. 装了mysql开发库之后（你Yum,build from source, emerge 等等），会顺便安装一个mysql_config的程序，它可以输出mysql的include和libs路径,  使用am工具可以在configure.ac写以下脚本，让用户自行给一个mysql_config的执行路径，或使用默认的来检测.
   configure.in
   AC_MSG_CHECKING(for MySQL support) 输出检查信息
   AC_ARG_WITH(mysql,
    AC_HELP_STRING([--with-mysql@<:@=PATH@:>@],[Include MySQL support. PATH is the path to 'mysql_config']),
    [WITH_MYSQL=$withval],[WITH_MYSQL=yes])
   
    <---定义一个configure配置项,withval 是用户输入值, yes设置默认值
   
    AC_PATH_PROG(MYSQL_CONFIG, mysql_config)
   
    AC_SUBST(MYSQL_LIBS) 替换Makefile.am中的变量 $(MYSQL_LIBS)
    AC_SUBST(MYSQL_INCLUDE) 替换Makefile.am中的变量 $(MYSQL_INCLUDE)
    完整检测代码:
       if test "$WITH_MYSQL" != "no"; then
      AC_MSG_RESULT(yes)
      if test "$WITH_MYSQL" = "yes" ; then
        AC_PATH_PROG(MYSQL_CONFIG, mysql_config)
      else
        MYSQL_CONFIG=$WITH_MYSQL
      fi
    dnl  AC_PATH_PROG(MYSQL_CONFIG, mysql_config)
    
      if test "$MYSQL_CONFIG" = ""; then
        AC_MSG_ERROR(mysql_config is not found)
      fi
      if test /! -x $MYSQL_CONFIG; then
        AC_MSG_ERROR(mysql_config not exists or not executable, use --with-mysql=path-to-mysql_config)
      fi
    
      if $MYSQL_CONFIG | grep -- '--include' > /dev/null ; then
        MYSQL_INCLUDE="`$MYSQL_CONFIG --include | sed s//'//g`"
      else
        MYSQL_INCLUDE="`$MYSQL_CONFIG --cflags | sed s//'//g`"
      fi
      MYSQL_LIBS="`$MYSQL_CONFIG --libs | sed s//'//g`"
    
      AC_MSG_CHECKING(for MySQL includes at)
      AC_MSG_RESULT($MYSQL_INCLUDE)
    
      AC_MSG_CHECKING(for MySQL libraries at)
      AC_MSG_RESULT($MYSQL_LIBS)
    dnl check for errmsg.h, which isn't installed by some versions of 3.21
      old_CPPFLAGS="$CPPFLAGS"
      CPPFLAGS="$CPPFLAGS $MYSQL_INCLUDE"
      AC_CHECK_HEADERS(errmsg.h mysql.h)
      CPPFLAGS="$old_CPPFLAGS"
    
      AC_DEFINE([HAVE_MYSQL], [1], [mysql support])
    else
      AC_MSG_RESULT(no)
    fi

2. 使用mysql监听的unix-domain socket来获得这些信息, 参考PHP的做法.