endian.h: use C-style comments and wrap the comment to 80 characters.

src/include/compat/endian.h

@@ -1,8 +1,13 @@
-// "License": Public Domain
-// I, Mathias Panzenböck, place this file hereby into the public domain. Use it at your own risk for whatever you like.
-// In case there are jurisdictions that don't support putting things in the public domain you can also consider it to
-// be "dual licensed" under the BSD, MIT and Apache licenses, if you want to. This code is trivial anyway. Consider it
-// an example on how to get the endian conversion functions on different platforms.
+/**
+ * "License": Public Domain
+ *
+ * I, Mathias Panzenböck, place this file hereby into the public domain. Use it
+ * at your own risk for whatever you like. In case there are jurisdictions that
+ * don't support putting things in the public domain you can also consider it
+ * to be "dual licensed" under the BSD, MIT and Apache licenses, if you want
+ * to. This code is trivial anyway. Consider it an example on how to get the
+ * endian conversion functions on different platforms.
+ */
 
 #ifndef PORTABLE_ENDIAN_H__
 #define PORTABLE_ENDIAN_H__