unix: provide Mount on openbsd

Note that Mount is already provided for both darwin and linux, with
differing signatures.

Change-Id: Iaddae1769e436aad5125b78e31b2d62d22e45b16
Reviewed-on: https://go-review.googlesource.com/c/sys/+/595735
Reviewed-by: Ian Lance Taylor <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>
Reviewed-by: Michael Knyszek <[email protected]>

Author: 4a6f656c

unix/syscall_openbsd.go

@@ -293,6 +293,7 @@ func Uname(uname *Utsname) error {
 //sys	Mkfifoat(dirfd int, path string, mode uint32) (err error)
 //sys	Mknod(path string, mode uint32, dev int) (err error)
 //sys	Mknodat(dirfd int, path string, mode uint32, dev int) (err error)
+//sys	Mount(fsType string, dir string, flags int, data unsafe.Pointer) (err error)
 //sys	Nanosleep(time *Timespec, leftover *Timespec) (err error)
 //sys	Open(path string, mode int, perm uint32) (fd int, err error)
 //sys	Openat(dirfd int, path string, mode int, perm uint32) (fd int, err error)

unix/zsyscall_openbsd_386.go

@@ -463,6 +463,11 @@ TEXT libc_mknodat_trampoline<>(SB),NOSPLIT,$0-0
 GLOBL	·libc_mknodat_trampoline_addr(SB), RODATA, $4
 DATA	·libc_mknodat_trampoline_addr(SB)/4, $libc_mknodat_trampoline<>(SB)
 
+TEXT libc_mount_trampoline<>(SB),NOSPLIT,$0-0
+	JMP	libc_mount(SB)
+GLOBL	·libc_mount_trampoline_addr(SB), RODATA, $4
+DATA	·libc_mount_trampoline_addr(SB)/4, $libc_mount_trampoline<>(SB)
+
 TEXT libc_nanosleep_trampoline<>(SB),NOSPLIT,$0-0
 	JMP	libc_nanosleep(SB)
 GLOBL	·libc_nanosleep_trampoline_addr(SB), RODATA, $4

unix/zsyscall_openbsd_386.s

@@ -463,6 +463,11 @@ TEXT libc_mknodat_trampoline<>(SB),NOSPLIT,$0-0
 GLOBL	·libc_mknodat_trampoline_addr(SB), RODATA, $8
 DATA	·libc_mknodat_trampoline_addr(SB)/8, $libc_mknodat_trampoline<>(SB)
 
+TEXT libc_mount_trampoline<>(SB),NOSPLIT,$0-0
+	JMP	libc_mount(SB)
+GLOBL	·libc_mount_trampoline_addr(SB), RODATA, $8
+DATA	·libc_mount_trampoline_addr(SB)/8, $libc_mount_trampoline<>(SB)
+
 TEXT libc_nanosleep_trampoline<>(SB),NOSPLIT,$0-0
 	JMP	libc_nanosleep(SB)
 GLOBL	·libc_nanosleep_trampoline_addr(SB), RODATA, $8

unix/zsyscall_openbsd_amd64.go

@@ -463,6 +463,11 @@ TEXT libc_mknodat_trampoline<>(SB),NOSPLIT,$0-0
 GLOBL	·libc_mknodat_trampoline_addr(SB), RODATA, $4
 DATA	·libc_mknodat_trampoline_addr(SB)/4, $libc_mknodat_trampoline<>(SB)
 
+TEXT libc_mount_trampoline<>(SB),NOSPLIT,$0-0
+	JMP	libc_mount(SB)
+GLOBL	·libc_mount_trampoline_addr(SB), RODATA, $4
+DATA	·libc_mount_trampoline_addr(SB)/4, $libc_mount_trampoline<>(SB)
+
 TEXT libc_nanosleep_trampoline<>(SB),NOSPLIT,$0-0
 	JMP	libc_nanosleep(SB)
 GLOBL	·libc_nanosleep_trampoline_addr(SB), RODATA, $4

unix/zsyscall_openbsd_amd64.s

@@ -463,6 +463,11 @@ TEXT libc_mknodat_trampoline<>(SB),NOSPLIT,$0-0
 GLOBL	·libc_mknodat_trampoline_addr(SB), RODATA, $8
 DATA	·libc_mknodat_trampoline_addr(SB)/8, $libc_mknodat_trampoline<>(SB)
 
+TEXT libc_mount_trampoline<>(SB),NOSPLIT,$0-0
+	JMP	libc_mount(SB)
+GLOBL	·libc_mount_trampoline_addr(SB), RODATA, $8
+DATA	·libc_mount_trampoline_addr(SB)/8, $libc_mount_trampoline<>(SB)
+
 TEXT libc_nanosleep_trampoline<>(SB),NOSPLIT,$0-0
 	JMP	libc_nanosleep(SB)
 GLOBL	·libc_nanosleep_trampoline_addr(SB), RODATA, $8