Added clearerr() to clear EOF state

Objects/fileobject.c

 /* File object implementation */
 
 #define PY_SSIZE_T_CLEAN
 #include "Python.h"
 #include "structmember.h"
 
 #ifdef HAVE_SYS_TYPES_H
 #include <sys/types.h>
 #endif /* HAVE_SYS_TYPES_H */
 
@@ skipping 2497 matching lines @@
         int newlinetypes = 0;
         int skipnextlf = 0;
         int univ_newline = 1;
 
         if (fobj) {
                 if (!PyFile_Check(fobj)) {
                         errno = ENXIO;  /* What can you do... */
                         return NULL;
                 }
                 univ_newline = ((PyFileObject *)fobj)->f_univ_newline;
-                if ( !univ_newline )
+                if ( !univ_newline ) {
+                        /* Issue #1706039: Support continued reading from a file even after
+                         * EOF was hit.
+                         */
+                        clearerr(stream);
                         return fgets(buf, n, stream);
+                }
                 newlinetypes = ((PyFileObject *)fobj)->f_newlinetypes;
                 skipnextlf = ((PyFileObject *)fobj)->f_skipnextlf;
         }
         FLOCKFILE(stream);
+        /* Issue #1706039: Support continued reading from a file even after
+         * EOF was hit.
+         */
+        clearerr(stream);
         c = 'x'; /* Shut up gcc warning */
         while (--n > 0 && (c = GETC(stream)) != EOF ) {
                 if (skipnextlf ) {
                         skipnextlf = 0;
                         if (c == '\n') {
                                 /* Seeing a \n here with skipnextlf true
                                 ** means we saw a \r before.
                                 */
                                 newlinetypes |= NEWLINE_CRLF;
                                 c = GETC(stream);
@@ skipping 62 matching lines @@
         PyFileObject *f = (PyFileObject *)fobj;
         int newlinetypes, skipnextlf;
 
         assert(buf != NULL);
         assert(stream != NULL);
 
         if (!fobj || !PyFile_Check(fobj)) {
                 errno = ENXIO;  /* What can you do... */
                 return 0;
         }
+        /* Issue #1706039: Support continued reading from a file even after
+         * EOF was hit.
+         */
+        clearerr(stream);
         if (!f->f_univ_newline)
                 return fread(buf, 1, n, stream);
         newlinetypes = f->f_newlinetypes;
         skipnextlf = f->f_skipnextlf;
         /* Invariant:  n is the number of bytes remaining to be filled
          * in the buffer.
          */
         while (n) {
                 size_t nread;
                 int shortread;
@@ skipping 40 matching lines @@
                 }
         }
         f->f_newlinetypes = newlinetypes;
         f->f_skipnextlf = skipnextlf;
         return dst - buf;
 }
 
 #ifdef __cplusplus
 }
 #endif