use c calling conventions so that g++ doesn't mangle fpgetmask &

friends' names unbreaking at least enblend-enfuse & inkscape on
macppc & alpha
reported, tested: ajacoutot@, sthen@
ok: millert@, otto@

src/include/ieeefp.h

@@ -1,4 +1,4 @@
-/*	$OpenBSD: ieeefp.h,v 1.3 2002/02/16 21:27:17 millert Exp $	*/
+/*	$OpenBSD: ieeefp.h,v 1.4 2009/09/27 21:23:55 martynas Exp $	*/
 
 /* 
  * Written by J.T. Conklin, Apr 6, 1995
@@ -11,11 +11,13 @@
 #include <sys/cdefs.h>
 #include <machine/ieeefp.h>
 
+__BEGIN_DECLS
 extern fp_rnd    fpgetround(void);
 extern fp_rnd    fpsetround(fp_rnd);
 extern fp_except fpgetmask(void);
 extern fp_except fpsetmask(fp_except);
 extern fp_except fpgetsticky(void);
 extern fp_except fpsetsticky(fp_except);
+__END_DECLS
 
 #endif /* _IEEEFP_H_ */