"restrict requires a pointer or reference" build failure(s) — clang 2.9

clang complains about the syntax (while gcc accepts it)
void foo()
{
    register int i, restrict;
}
PackageVersionSupposed error messageFull log Bug report
cdecl 2.5-11cdecl.c:244:24: error: expected identifier or '(' Log
icheck 0.9.7-6.1PerlXS.xs:1721:17: error: expected identifier or '(' Log
pcp 3.5.7logger.c:367:39: error: expected identifier or '(' Log
sofia-sip 1.12.11+20110422-1./sofia-sip/sip_extra.h:2:1: error: expected identifier or '(' before '}' token Log

4 errors