Read in text mode, write in binary mode on OS/2

This enables to convert CR+LF to LF when reading, but disables to
convert LF to CR+LF when writing.

Instead, however, CR+LF are not passed into mksh as is.

exec.c

@@ -901,6 +901,9 @@ scriptexec(struct op *tp, const char **ap)
 		unsigned short m;
 		ssize_t n;
 
+#ifdef __OS2__
+		setmode(fd, O_TEXT);
+#endif
 		/* read first couple of octets from file */
 		n = read(fd, buf, sizeof(buf) - 1);
 		close(fd);