fix many internal links

Fixed a number of internal links that need to
go to the GitHub site.

Ran `make www` to perform the above.

2020/endoh1/README.md

@@ -34,7 +34,7 @@ code](#alternate-code) below.
 
 ## Alternate code:
 
-An alternate version of this entry, [prog.alt.c](prog.alt.c), is provided.  This
+An alternate version of this entry, [prog.alt.c](%%REPO_URL%%/2020/endoh1/prog.alt.c), is provided.  This
 alternate code lacks the additional rule to flag all unprobed cells.  See the
 Author's remarks for more details.
 
@@ -217,13 +217,13 @@ There are mines in a cell whose "priorities-of-each-cell" is less than
 ### Bug fixes and Credits
 
 The judges pointed out a bug of the original version that I submitted
-([prog.alt.c](prog.alt.c)).  Because this program does not provide a feature to
+([prog.alt.c](%%REPO_URL%%/2020/endoh1/prog.alt.c)).  Because this program does not provide a feature to
 flag unprobed cells manually, we can do nothing if the number of unprobed cells
 are equal to the number of mines remaining; [unwinnable.txt](unwinnable.txt) is
 an example for such a case.
 
 Thus, I implemented an additional rule to flag all unprobed cells in such a case
-into the final version ([prog.c](prog.c)).
+into the final version ([prog.c](%%REPO_URL%%/2020/endoh1/prog.c)).
 
 [Ilya Kurdyukov](../../authors.html#Ilya_Kurdyukov) also pointed out a warning
 "ignoring return value of 'fscanf'" only when `-O3` is used.  So I changed the

2020/endoh1/index.html

@@ -396,7 +396,7 @@ code</a> below.</p>
 
     ./prog unwinnable.txt</code></pre>
 <h2 id="alternate-code">Alternate code:</h2>
-<p>An alternate version of this entry, <a href="prog.alt.c">prog.alt.c</a>, is provided. This
+<p>An alternate version of this entry, <a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/endoh1/prog.alt.c">prog.alt.c</a>, is provided. This
 alternate code lacks the additional rule to flag all unprobed cells. See the
 Author’s remarks for more details.</p>
 <h3 id="alternate-build">Alternate build:</h3>
@@ -499,12 +499,12 @@ Analyze the code.</p>
 “number-of-mines”. (But the mine in the first-clicked cell is removed.)</p>
 <h3 id="bug-fixes-and-credits">Bug fixes and Credits</h3>
 <p>The judges pointed out a bug of the original version that I submitted
-(<a href="prog.alt.c">prog.alt.c</a>). Because this program does not provide a feature to
+(<a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/endoh1/prog.alt.c">prog.alt.c</a>). Because this program does not provide a feature to
 flag unprobed cells manually, we can do nothing if the number of unprobed cells
 are equal to the number of mines remaining; <a href="unwinnable.txt">unwinnable.txt</a> is
 an example for such a case.</p>
 <p>Thus, I implemented an additional rule to flag all unprobed cells in such a case
-into the final version (<a href="prog.c">prog.c</a>).</p>
+into the final version (<a href="https://github.com/ioccc-src/temp-test-ioccc/blob/master/2020/endoh1/prog.c">prog.c</a>).</p>
 <p><a href="../../authors.html#Ilya_Kurdyukov">Ilya Kurdyukov</a> also pointed out a warning
 “ignoring return value of ‘fscanf’” only when <code>-O3</code> is used. So I changed the
 code a little to pretend to use the return value of <code>fscanf(3)</code>.</p>