solaris: fix compilation failure

This patch fixes a compilation failure on Solaris. Compiler does
not support when a function returning void is used in return of
an other function returning void.

Patch obtained thanks to coccinelle and the following semantic
patch:

 @@
 identifier f;
 expression E;
 @@

 void f(...)
 {
 	<...
 	- return E;
 	+ E;
 	+ return;
 	...>
 }