Index: configure
===================================================================
--- configure	(revision 22712)
+++ configure	(working copy)
@@ -3568,6 +3568,11 @@
 cc_check && _sysi86=yes
 if test "$_sysi86" = yes ; then
   _def_sysi86='#define HAVE_SYSI86 1'
+  cat > $TMPC << EOF
+  #include <sys/sysi86.h>
+  int main (void) { int sysi86(int, void*); sysi86(0); return 0; }
+EOF
+  cc_check && _def_sysi86_iv='#define HAVE_SYSI86_iv 1'
 else
   _def_sysi86='#undef HAVE_SYSI86'
 fi
@@ -7917,6 +7922,7 @@
 
 /* Define this if your system has sysi86 */
 $_def_sysi86
+$_def_sysi86_iv
 
 /* Define this if your system has pthreads */
 $_def_pthreads
Index: loader/ldt_keeper.c
===================================================================
--- loader/ldt_keeper.c	(revision 22712)
+++ loader/ldt_keeper.c	(working copy)
@@ -62,8 +62,8 @@
 #include <sys/segment.h>
 #include <sys/sysi86.h>
 
-/* solaris x86: add missing prototype for sysi86() */
-#ifdef HAVE_SYSI86
+/* solaris x86: add missing prototype for sysi86(), but only when sysi86(int, void*) is known to be valid */
+#ifdef HAVE_SYSI86_iv
 #ifdef  __cplusplus
 extern "C" {
 #endif