尝试在编译示例程序时包含 -I 选项以指定 openssl 目录。
这是来自 openssl 目录中的 INSTALL 文件:
  *  WRITING applications
     To write an application that is able to handle both the new
     and the old directory layout, so that it can still be compiled
     with library versions up to OpenSSL 0.9.2b without bothering
     the user, you can proceed as follows:
     -  Always use the new filename of OpenSSL header files,
        e.g. #include <openssl/ssl.h>.
     -  Create a directory "incl" that contains only a symbolic
        link named "openssl", which points to the "include" directory
        of OpenSSL.
        For example, your application's Makefile might contain the
        following rule, if OPENSSLDIR is a pathname (absolute or
        relative) of the directory where OpenSSL resides:
        incl/openssl:
                -mkdir incl
                cd $(OPENSSLDIR) # Check whether the directory really exists
                -ln -s `cd $(OPENSSLDIR); pwd`/include incl/openssl
        You will have to add "incl/openssl" to the dependencies
        of those C files that include some OpenSSL header file.
     -  Add "-Iincl" to your CFLAGS.
     With these additions, the OpenSSL header files will be available
     under both name variants if an old library version is used:
     Your application can reach them under names like <openssl/foo.h>,
     while the header files still are able to #include each other
     with names of the form <foo.h>.
我建议您阅读 openssl 源目录中的 INSTALL 文件以获取更多详细信息。