libgo: permit loff_t and off_t to be macros

They are macros in musl libc, rather than typedefs, and -fgo-dump-spec
doesn't handle that case.

Based on patch by Sören Tempel.

Change-Id: Ic9a608fd964a6f78e754aa8e3100aff06ab3dade
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/412075
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
diff --git a/libgo/config.h.in b/libgo/config.h.in
index 25b8ab8..2c3c746 100644
--- a/libgo/config.h.in
+++ b/libgo/config.h.in
@@ -70,6 +70,9 @@
 /* Define to 1 if you have the `fchownat' function. */
 #undef HAVE_FCHOWNAT
 
+/* Define to 1 if you have the <fcntl.h> header file. */
+#undef HAVE_FCNTL_H
+
 /* Define to 1 if you have the `futimesat' function. */
 #undef HAVE_FUTIMESAT
 
diff --git a/libgo/configure b/libgo/configure
index ffe17c9..b7ff9b3 100755
--- a/libgo/configure
+++ b/libgo/configure
@@ -15249,7 +15249,7 @@
   fi
 
 
-for ac_header in port.h sched.h semaphore.h sys/file.h sys/mman.h syscall.h sys/epoll.h sys/event.h sys/inotify.h sys/ptrace.h sys/syscall.h sys/sysctl.h sys/user.h sys/utsname.h sys/select.h sys/socket.h net/bpf.h net/if.h net/if_arp.h net/route.h netpacket/packet.h sys/prctl.h sys/mount.h sys/vfs.h sys/statfs.h sys/timex.h sys/sysinfo.h utime.h linux/ether.h linux/fs.h linux/ptrace.h linux/reboot.h netinet/in_syst.h netinet/ip.h netinet/ip_mroute.h netinet/if_ether.h lwp.h
+for ac_header in fcntl.h port.h sched.h semaphore.h sys/file.h sys/mman.h syscall.h sys/epoll.h sys/event.h sys/inotify.h sys/ptrace.h sys/syscall.h sys/sysctl.h sys/user.h sys/utsname.h sys/select.h sys/socket.h net/bpf.h net/if.h net/if_arp.h net/route.h netpacket/packet.h sys/prctl.h sys/mount.h sys/vfs.h sys/statfs.h sys/timex.h sys/sysinfo.h utime.h linux/ether.h linux/fs.h linux/ptrace.h linux/reboot.h netinet/in_syst.h netinet/ip.h netinet/ip_mroute.h netinet/if_ether.h lwp.h
 do :
   as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
 ac_fn_c_check_header_mongrel "$LINENO" "$ac_header" "$as_ac_Header" "$ac_includes_default"
@@ -15546,7 +15546,11 @@
 
 fi
 
-ac_fn_c_check_type "$LINENO" "loff_t" "ac_cv_type_loff_t" "$ac_includes_default"
+
+CFLAGS_hold="$CFLAGS"
+CFLAGS="$OSCFLAGS $CFLAGS"
+ac_fn_c_check_type "$LINENO" "loff_t" "ac_cv_type_loff_t" "#include <fcntl.h>
+"
 if test "x$ac_cv_type_loff_t" = xyes; then :
 
 cat >>confdefs.h <<_ACEOF
@@ -15556,6 +15560,7 @@
 
 fi
 
+CFLAGS="$CFLAGS_hold"
 
 LIBS_hold="$LIBS"
 LIBS="$LIBS -lm"
diff --git a/libgo/configure.ac b/libgo/configure.ac
index 7e2b98b..bac58b0 100644
--- a/libgo/configure.ac
+++ b/libgo/configure.ac
@@ -579,7 +579,7 @@
 
 GCC_CHECK_UNWIND_GETIPINFO
 
-AC_CHECK_HEADERS(port.h sched.h semaphore.h sys/file.h sys/mman.h syscall.h sys/epoll.h sys/event.h sys/inotify.h sys/ptrace.h sys/syscall.h sys/sysctl.h sys/user.h sys/utsname.h sys/select.h sys/socket.h net/bpf.h net/if.h net/if_arp.h net/route.h netpacket/packet.h sys/prctl.h sys/mount.h sys/vfs.h sys/statfs.h sys/timex.h sys/sysinfo.h utime.h linux/ether.h linux/fs.h linux/ptrace.h linux/reboot.h netinet/in_syst.h netinet/ip.h netinet/ip_mroute.h netinet/if_ether.h lwp.h)
+AC_CHECK_HEADERS(fcntl.h port.h sched.h semaphore.h sys/file.h sys/mman.h syscall.h sys/epoll.h sys/event.h sys/inotify.h sys/ptrace.h sys/syscall.h sys/sysctl.h sys/user.h sys/utsname.h sys/select.h sys/socket.h net/bpf.h net/if.h net/if_arp.h net/route.h netpacket/packet.h sys/prctl.h sys/mount.h sys/vfs.h sys/statfs.h sys/timex.h sys/sysinfo.h utime.h linux/ether.h linux/fs.h linux/ptrace.h linux/reboot.h netinet/in_syst.h netinet/ip.h netinet/ip_mroute.h netinet/if_ether.h lwp.h)
 
 AC_CHECK_HEADERS([netinet/icmp6.h], [], [],
 [#include <netinet/in.h>
@@ -601,7 +601,11 @@
 
 AC_CHECK_FUNCS(accept4 dup3 epoll_create1 faccessat fallocate fchmodat fchownat futimesat getxattr inotify_add_watch inotify_init inotify_init1 inotify_rm_watch listxattr mkdirat mknodat open64 openat pipe2 removexattr renameat setxattr sync_file_range splice syscall tee unlinkat unshare utimensat)
 AC_TYPE_OFF_T
-AC_CHECK_TYPES([loff_t])
+
+CFLAGS_hold="$CFLAGS"
+CFLAGS="$OSCFLAGS $CFLAGS"
+AC_CHECK_TYPES([loff_t], [], [], [[#include <fcntl.h>]])
+CFLAGS="$CFLAGS_hold"
 
 LIBS_hold="$LIBS"
 LIBS="$LIBS -lm"
diff --git a/libgo/go/syscall/libcall_linux.go b/libgo/go/syscall/libcall_linux.go
index 7bec2fb..19ae439 100644
--- a/libgo/go/syscall/libcall_linux.go
+++ b/libgo/go/syscall/libcall_linux.go
@@ -210,20 +210,20 @@
 //sys	Setxattr(path string, attr string, data []byte, flags int) (err error)
 //setxattr(path *byte, name *byte, value *byte, size Size_t, flags _C_int) _C_int
 
-//sys	splice(rfd int, roff *_loff_t, wfd int, woff *_loff_t, len int, flags int) (n int64, err error)
-//splice(rfd _C_int, roff *_loff_t, wfd _C_int, woff *_loff_t, len Size_t, flags _C_uint) Ssize_t
+//sys	splice(rfd int, roff *_libgo_loff_t_type, wfd int, woff *_libgo_loff_t_type, len int, flags int) (n int64, err error)
+//splice(rfd _C_int, roff *_libgo_loff_t_type, wfd _C_int, woff *_libgo_loff_t_type, len Size_t, flags _C_uint) Ssize_t
 
 func Splice(rfd int, roff *int64, wfd int, woff *int64, len int, flags int) (n int64, err error) {
-	var lroff _loff_t
-	var plroff *_loff_t
+	var lroff _libgo_loff_t_type
+	var plroff *_libgo_loff_t_type
 	if roff != nil {
-		lroff = _loff_t(*roff)
+		lroff = _libgo_loff_t_type(*roff)
 		plroff = &lroff
 	}
-	var lwoff _loff_t
-	var plwoff *_loff_t
+	var lwoff _libgo_loff_t_type
+	var plwoff *_libgo_loff_t_type
 	if woff != nil {
-		lwoff = _loff_t(*woff)
+		lwoff = _libgo_loff_t_type(*woff)
 		plwoff = &lwoff
 	}
 	n, err = splice(rfd, plroff, wfd, plwoff, len, flags)
diff --git a/libgo/mksysinfo.sh b/libgo/mksysinfo.sh
index 0c52ea5..5aa3091 100755
--- a/libgo/mksysinfo.sh
+++ b/libgo/mksysinfo.sh
@@ -403,11 +403,7 @@
 # Some basic types.
 echo 'type Size_t _size_t' >> ${OUT}
 echo "type Ssize_t _ssize_t" >> ${OUT}
-if grep '^const _HAVE_OFF64_T = ' gen-sysinfo.go > /dev/null 2>&1; then
-  echo "type Offset_t _off64_t" >> ${OUT}
-else
-  echo "type Offset_t _off_t" >> ${OUT}
-fi
+echo "type Offset_t _libgo_off_t_type" >> ${OUT}
 echo "type Mode_t _mode_t" >> ${OUT}
 echo "type Pid_t _pid_t" >> ${OUT}
 echo "type Uid_t _uid_t" >> ${OUT}
diff --git a/libgo/sysinfo.c b/libgo/sysinfo.c
index 8ce061e..a4259c0 100644
--- a/libgo/sysinfo.c
+++ b/libgo/sysinfo.c
@@ -357,6 +357,18 @@
 };
 #endif
 
+#if defined(HAVE_LOFF_T)
+// loff_t can be defined as a macro; for -fgo-dump-spec make sure we
+// see a typedef.
+typedef loff_t libgo_loff_t_type;
+#endif
+
+#if defined(HAVE_OFF64_T)
+typedef off64_t libgo_off_t_type;
+#else
+typedef off_t libgo_off_t_type;
+#endif
+
 // The following section introduces explicit references to types and
 // constants of interest to support bootstrapping libgo using a
 // compiler that doesn't support -fdump-go-spec (e.g., clang), via
@@ -537,7 +549,8 @@
 // From sys/types.h
 TREF(pid_t);
 TREF(off_t);
-TREF(loff_t);
+TREF(libgo_loff_t_type);
+TREF(libgo_off_t_type);
 TREF(size_t);
 TREF(ssize_t);
 TREF(mode_t);