Make setjmp, longjmp, sigsetjmp, and siglongjmp weak aliases for

__setjmp, __longjmp, __sigsetjmp, and __siglongjmp, respectively.
This supports cancellation in the linuxthreads port.  In the long run,
a much more comprehensive solution will necessitate more dramatic changes
to libc symbol naming, and these aliases will probably need modification
at that time.

lib/libc/amd64/gen/setjmp.S

@@ -54,7 +54,9 @@
 #include "DEFS.h"
 #include "SYS.h"
 
-ENTRY(setjmp)
+ENTRY(__setjmp)
+.weak setjmp;
+.set setjmp, __setjmp;
 	movl	4(%esp),%ecx
 	PIC_PROLOGUE
 	leal	28(%ecx), %eax
@@ -80,7 +82,9 @@ ENTRY(setjmp)
 	xorl	%eax,%eax
 	ret
 
-ENTRY(longjmp)
+ENTRY(__longjmp)
+.weak longjmp;
+.set longjmp, __longjmp;
 	movl	4(%esp),%edx
 	PIC_PROLOGUE
 	pushl	$0			/* (sigset_t*)oset */

lib/libc/amd64/gen/sigsetjmp.S

@@ -59,7 +59,9 @@
  *	use sigreturn() if sigreturn() works.
  */
 
-ENTRY(sigsetjmp)
+ENTRY(__sigsetjmp)
+.weak sigsetjmp;
+.set sigsetjmp, __sigsetjmp;
 	movl	8(%esp),%eax
 	movl	4(%esp),%ecx
 	movl	%eax,44(%ecx)
@@ -89,7 +91,9 @@ ENTRY(sigsetjmp)
 	xorl	%eax,%eax
 	ret
 
-ENTRY(siglongjmp)
+ENTRY(__siglongjmp)
+.weak siglongjmp;
+.set siglongjmp, __siglongjmp;
 	movl	4(%esp),%edx
 	cmpl	$0,44(%edx)
 	jz	2f

lib/libc/i386/gen/setjmp.S

@@ -54,7 +54,9 @@
 #include "DEFS.h"
 #include "SYS.h"
 
-ENTRY(setjmp)
+ENTRY(__setjmp)
+.weak setjmp;
+.set setjmp, __setjmp;
 	movl	4(%esp),%ecx
 	PIC_PROLOGUE
 	leal	28(%ecx), %eax
@@ -80,7 +82,9 @@ ENTRY(setjmp)
 	xorl	%eax,%eax
 	ret
 
-ENTRY(longjmp)
+ENTRY(__longjmp)
+.weak longjmp;
+.set longjmp, __longjmp;
 	movl	4(%esp),%edx
 	PIC_PROLOGUE
 	pushl	$0			/* (sigset_t*)oset */

lib/libc/i386/gen/sigsetjmp.S

@@ -59,7 +59,9 @@
  *	use sigreturn() if sigreturn() works.
  */
 
-ENTRY(sigsetjmp)
+ENTRY(__sigsetjmp)
+.weak sigsetjmp;
+.set sigsetjmp, __sigsetjmp;
 	movl	8(%esp),%eax
 	movl	4(%esp),%ecx
 	movl	%eax,44(%ecx)
@@ -89,7 +91,9 @@ ENTRY(sigsetjmp)
 	xorl	%eax,%eax
 	ret
 
-ENTRY(siglongjmp)
+ENTRY(__siglongjmp)
+.weak siglongjmp;
+.set siglongjmp, __siglongjmp;
 	movl	4(%esp),%edx
 	cmpl	$0,44(%edx)
 	jz	2f