*/string.3,arch.7,environ.7: add cross-references to simd(7)

With the new simd-dispatch framework documented in simd(7),
add cross-references to the new man pages to appropriate places.

Sponsored by:	The FreeBSD Foundation
Approved by:	emaste
MFC to:		stable/14
MFC after:	3 days
Differential Revision: https://reviews.freebsd.org/D41697

lib/libc/string/string.3

@@ -29,7 +29,7 @@
 .\"
 .\"     @(#)string.3	8.2 (Berkeley) 12/11/93
 .\"
-.Dd December 11, 1993
+.Dd September 2, 2023
 .Dt STRING 3
 .Os
 .Sh NAME
@@ -132,7 +132,8 @@ for size limitations.
 .Xr strsep 3 ,
 .Xr strspn 3 ,
 .Xr strstr 3 ,
-.Xr strtok 3
+.Xr strtok 3 ,
+.Xr simd 7
 .Sh STANDARDS
 The
 .Fn strcat ,

share/man/man7/arch.7

@@ -24,7 +24,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd April 12, 2023
+.Dd September 2, 2023
 .Dt ARCH 7
 .Os
 .Sh NAME
@@ -431,7 +431,8 @@ it is unused outside of that scope.
 .El
 .Sh SEE ALSO
 .Xr src.conf 5 ,
-.Xr build 7
+.Xr build 7 ,
+.Xr simd 7
 .Sh HISTORY
 An
 .Nm

share/man/man7/environ.7

@@ -27,7 +27,7 @@
 .\"
 .\"	@(#)environ.7	8.3 (Berkeley) 4/19/94
 .\"
-.Dd August 5, 2020
+.Dd September 3, 2023
 .Dt ENVIRON 7
 .Os
 .Sh NAME
@@ -66,6 +66,13 @@ are documented in the
 section of the appropriate manual page.
 .Sh ENVIRONMENT
 .Bl -tag -width LD_LIBRARY_PATH
+.It Ev ARCHLEVEL
+On
+.Em amd64 ,
+controls the level of SIMD enhancements used.
+See
+.Xr simd 7
+for details.
 .It Ev BLOCKSIZE
 The size of the block units used by several disk-related commands,
 most notably
@@ -305,7 +312,8 @@ built-in command in
 .Xr setlocale 3 ,
 .Xr system 3 ,
 .Xr termcap 3 ,
-.Xr termcap 5
+.Xr termcap 5 ,
+.Xr simd 7
 .Sh HISTORY
 The
 .Nm