Change alt/orig to build/to use heading levels

As the 'Alternate code' and 'Original code' heading level is now 2 the
'To build' and 'To use' subsections should be level 3, not 4, and also
reworded, this was done:

    sgit -e 's/^#### To build/### Alternate build/g' -e 's/^#### To use/### Alternate use/g' '*README.md'

Many more have to be updated and this will be done manually at another
time.

1985/lycklama/README.md

@@ -63,13 +63,13 @@ appreciate what it does, we encourage you to first try the alternate version.
 After this, however, you might wish to try the original version, fixed for
 modern systems.
 
-#### To build:
+### Alternate build:
 
 ```sh
 make all
 ```
 
-#### To use:
+### Alternate use:
 
 
 ```sh

1985/sicherman/README.md

@@ -32,14 +32,14 @@ This alternate version, which is the original entry, requires either an old
 enough compiler or a compiler that supports `-traditional-cpp`. If you have such
 a compiler you can try this version.
 
-#### To build:
+### Alternate build:
 
 
 ```sh
 make alt
 ```
 
-#### To use:
+### Alternate use:
 
 ```sh
 ./sicherman.alt < file