hdf5_ep

[svn-r18327] I commented out the macro H5_HAVE_SYMLINK because I ran the following C test under hdf5/test
directory.  OpenVMS couldn't open a file through symbolic link.  This macro is mainly used
in test/links.c for the function call external_symlink and in src/H5F.c.

Tested on OpenVMS.

------------------------------------------------------------------------
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>

int main(void)
{
    int file1, file2;

    /* Create a symbolic link to the file 21b.c */
    if(symlink("[LU.hdf5_1_8_2_5.test.tmp2]21b.c", "[LU.hdf5_1_8_2_5.test.tmp]sym1") < 0)
        printf("symlink failed\n");

    /* Create the file 21b.c */
    if((file1 = open("[LU.hdf5_1_8_2_5.test.tmp2]21b.c", O_CREAT | O_TRUNC | O_RDWR)) < 0)
        printf("1st open failed\n");

    if(close(file1) < 0)
        printf("close failed\n");

    /* Open the 21b.c through the symbolic link */
    if((file2 = open("[LU.hdf5_1_8_2_5.test.tmp]sym1", O_RDWR)) < 0) {
        int errsv = errno;
        printf("2nd open failed, errno=%d\n", errsv);
    }

    if(close(file2) < 0)
        printf("close failed\n");

    return 0;
}