files: block the resizing signal while reading from an external command

A SIGWINCH somehow causes the input stream to see EOT, with the result
that any remaining output of an external program would be lost.

This fixes https://savannah.gnu.org/bugs/?56038,
and fixes https://savannah.gnu.org/bugs/?56033.

Signed-off-by: Brand Huntsman <alpha@qzx.com>

src/files.c

@@ -800,6 +800,10 @@ void read_file(FILE *f, int fd, const char *filename, bool undoable)
 	topline = make_new_node(NULL);
 	bottomline = topline;
 
+#ifndef NANO_TINY
+	block_sigwinch(TRUE);
+#endif
+
 	/* Lock the file before starting to read it, to avoid the overhead
 	 * of locking it for each single byte that we read from it. */
 	flockfile(f);
@@ -875,6 +879,10 @@ void read_file(FILE *f, int fd, const char *filename, bool undoable)
 	/* We are done with the file, unlock it. */
 	funlockfile(f);
 
+#ifndef NANO_TINY
+	block_sigwinch(FALSE);
+#endif
+
 	/* Perhaps this could use some better handling. */
 	if (ferror(f))
 		nperror(filename);