Remove _THREAD_SAFE and make libc thread-safe by default by

adding (weak definitions to) stubs for some of the pthread
functions.  If the threads library is linked in, the real
pthread functions will pulled in.

Use the following convention for system calls wrapped by the
threads library:
	__sys_foo - actual system call
	_foo - weak definition to __sys_foo
	foo - weak definition to __sys_foo

Change all libc uses of system calls wrapped by the threads
library from foo to _foo.  In order to define the prototypes
for _foo(), we introduce namespace.h and un-namespace.h
(suggested by bde).  All files that need to reference these
system calls, should include namespace.h before any standard
includes, then include un-namespace.h after the standard
includes and before any local includes.  <db.h> is an exception
and shouldn't be included in between namespace.h and
un-namespace.h  namespace.h will define foo to _foo, and
un-namespace.h will undefine foo.

Try to eliminate some of the recursive calls to MT-safe
functions in libc/stdio in preparation for adding a mutex
to FILE.  We have recursive mutexes, but would like to avoid
using them if possible.

Remove uneeded includes of <errno.h> from a few files.

Add $FreeBSD$ to a few files in order to pass commitprep.

Approved by:	-arch

3 files changed, 8 insertions, 32 deletions

diff --git a/lib/libc/alpha/gen/_setjmp.S b/lib/libc/alpha/gen/_setjmp.S
index 0d032e7..f3aa6ff 100644
--- a/lib/libc/alpha/gen/_setjmp.S
+++ b/lib/libc/alpha/gen/_setjmp.S
@@ -87,12 +87,8 @@ LEAF(_setjmp, 1)
 	RET
 END(_setjmp)
 
-#ifdef _THREAD_SAFE
+XLEAF(_longjmp, 2)
 LEAF(___longjmp, 2)
-#else
-XLEAF(___longjmp, 2)
-LEAF(_longjmp, 2)
-#endif
 	LDGP(pv)
 	ldq	t0, ((31 + 4) * 8)(a0)		/* magic in sc_regs[31] */
 	ldiq	t1, 0xacedbadd
@@ -127,8 +123,4 @@ botch:
 	CALL(longjmperror)
 	CALL(abort)
 	RET					/* "can't" get here... */
-#ifdef _THREAD_SAFE
 END(___longjmp)
-#else
-END(_longjmp)
-#endif
diff --git a/lib/libc/alpha/gen/setjmp.S b/lib/libc/alpha/gen/setjmp.S
index 04202ce..297e601 100644
--- a/lib/libc/alpha/gen/setjmp.S
+++ b/lib/libc/alpha/gen/setjmp.S
@@ -66,12 +66,12 @@ LEAF(setjmp, 1)
 	lda	a2, (71 * 8)(a0)		/* oset: sc_reserved */
 	mov	zero, a1			/* set:	 NULL */
 	addq	a1, 1, a0			/* how:	 SIG_BLOCK */
-	PCALL(sigprocmask)			/* see what's blocked */
+	CALL(_sigprocmask)			/* see what's blocked */
 
 	lda	sp, -24(sp)			/* sizeof struct sigaltstack */
 	mov	zero, a0
 	mov	sp, a1
-	PCALL(sigaltstack)
+	CALL(_sigaltstack)
 	ldl	t0, 16(sp)			/* offset of ss_flags */
 	lda	sp, 24(sp)			/* sizeof struct sigaltstack */
 	ldq	ra, ((26 + 4) * 8)(s0)		/* restore return address */
@@ -115,22 +115,14 @@ LEAF(setjmp, 1)
 	RET
 END(setjmp)
 
-#ifdef _THREAD_SAFE
+XLEAF(longjmp, 2)
 LEAF(__longjmp, 2)
-#else
-XLEAF(__longjmp, 2)
-LEAF(longjmp, 2)
-#endif
 	LDGP(pv)
 	stq	a1, (( 0 + 4) * 8)(a0)		/* save return value */
-	PCALL(sigreturn)			/* use sigreturn to return */
+	CALL(_sigreturn)			/* use sigreturn to return */
 
 botch:
 	CALL(longjmperror)
 	CALL(abort)
 	RET					/* "can't" get here... */
-#ifdef _THREAD_SAFE
 END(__longjmp)
-#else
-END(longjmp)
-#endif
diff --git a/lib/libc/alpha/gen/sigsetjmp.S b/lib/libc/alpha/gen/sigsetjmp.S
index 0a3992d..ddc0636 100644
--- a/lib/libc/alpha/gen/sigsetjmp.S
+++ b/lib/libc/alpha/gen/sigsetjmp.S
@@ -54,20 +54,12 @@ Lsavesig:
 	jmp	zero, setjmp
 END(sigsetjmp)
 
-#ifdef _THREAD_SAFE
+XLEAF(siglongjmp, 2)
 LEAF(__siglongjmp, 2)
-#else
-XLEAF(__siglongjmp, 2)
-LEAF(siglongjmp, 2)
-#endif
 	LDGP(pv)
 	ldq	t0, (81 * 8)(a0)		/* get the mask */
 	bne	t0, Lrestoresig			/* if !zero, restore signals */
-	jmp	zero, _longjmp
+	jmp	zero, ___longjmp
 Lrestoresig:
-	jmp	zero, longjmp
-#ifdef _THREAD_SAFE
+	jmp	zero, __longjmp
 END(__siglongjmp)
-#else
-END(siglongjmp)
-#endif