Add cross-compilation guesses for Linux systems without glibc.

* m4/chown.m4 (AC_FUNC_CHOWN): Add cross-compilation guess for Linux.
* m4/fchdir.m4 (gl_FUNC_FCHDIR): Likewise.
* m4/link.m4 (gl_FUNC_LINK): Likewise.
* m4/linkat.m4 (gl_FUNC_LINKAT): Likewise.
* m4/lstat.m4 (gl_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK): Likewise.
* m4/mkdir.m4 (gl_FUNC_MKDIR): Likewise.
* m4/mkfifo.m4 (gl_FUNC_MKFIFO): Likewise.
* m4/mknod.m4 (gl_FUNC_MKNOD): Likewise.
* m4/pselect.m4 (gl_FUNC_PSELECT): Likewise.
* m4/readlink.m4 (gl_FUNC_READLINK): Likewise.
* m4/rename.m4 (gl_FUNC_RENAME): Likewise.
* m4/rmdir.m4 (gl_FUNC_RMDIR): Likewise.
* m4/select.m4 (gl_FUNC_SELECT): Likewise.
* m4/stat.m4 (gl_FUNC_STAT): Likewise.
* m4/symlink.m4 (gl_FUNC_SYMLINK): Likewise.
* m4/symlinkat.m4 (gl_FUNC_SYMLINKAT): Likewise.
* m4/unlink.m4 (gl_FUNC_UNLINK): Likewise.
* m4/utimens.m4 (gl_UTIMENS): Likewise.

18 files changed, 164 insertions, 119 deletions

diff --git a/m4/chown.m4 b/m4/chown.m4
index a3cd32ad41..600ee934d1 100644
--- a/m4/chown.m4
+++ b/m4/chown.m4
@@ -1,4 +1,4 @@
-# serial 29
+# serial 30
 # Determine whether we need the chown wrapper.
 
 dnl Copyright (C) 1997-2001, 2003-2005, 2007, 2009-2018 Free Software
@@ -46,12 +46,14 @@ AC_DEFUN([AC_FUNC_CHOWN],
        [ac_cv_func_chown_works=yes],
        [ac_cv_func_chown_works=no],
        [case "$host_os" in # ((
-                         # Guess yes on glibc systems.
-          *-gnu* | gnu*) ac_cv_func_chown_works="guessing yes" ;;
-                         # Guess no on native Windows.
-          mingw*)        ac_cv_func_chown_works="guessing no" ;;
-                         # If we don't know, assume the worst.
-          *)             ac_cv_func_chown_works="guessing no" ;;
+                           # Guess yes on Linux systems.
+          linux-* | linux) ac_cv_func_chown_works="guessing yes" ;;
+                           # Guess yes on glibc systems.
+          *-gnu* | gnu*)   ac_cv_func_chown_works="guessing yes" ;;
+                           # Guess no on native Windows.
+          mingw*)          ac_cv_func_chown_works="guessing no" ;;
+                           # If we don't know, assume the worst.
+          *)               ac_cv_func_chown_works="guessing no" ;;
         esac
        ])
      rm -f conftest.chown
diff --git a/m4/fchdir.m4 b/m4/fchdir.m4
index b621ae216e..470b228f7f 100644
--- a/m4/fchdir.m4
+++ b/m4/fchdir.m4
@@ -1,4 +1,4 @@
-# fchdir.m4 serial 23
+# fchdir.m4 serial 24
 dnl Copyright (C) 2006-2018 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -31,12 +31,14 @@ AC_DEFUN([gl_FUNC_FCHDIR],
         [gl_cv_func_open_directory_works=yes],
         [gl_cv_func_open_directory_works=no],
         [case "$host_os" in
-                          # Guess yes on glibc systems.
-           *-gnu* | gnu*) gl_cv_func_open_directory_works="guessing yes" ;;
-                          # Guess no on native Windows.
-           mingw*)        gl_cv_func_open_directory_works="guessing no" ;;
-                          # If we don't know, assume the worst.
-           *)             gl_cv_func_open_directory_works="guessing no" ;;
+                            # Guess yes on Linux systems.
+           linux-* | linux) gl_cv_func_open_directory_works="guessing yes" ;;
+                            # Guess yes on glibc systems.
+           *-gnu* | gnu*)   gl_cv_func_open_directory_works="guessing yes" ;;
+                            # Guess no on native Windows.
+           mingw*)          gl_cv_func_open_directory_works="guessing no" ;;
+                            # If we don't know, assume the worst.
+           *)               gl_cv_func_open_directory_works="guessing no" ;;
          esac
         ])])
     case "$gl_cv_func_open_directory_works" in
diff --git a/m4/link.m4 b/m4/link.m4
index b0b3ff25b8..d06b4f299a 100644
--- a/m4/link.m4
+++ b/m4/link.m4
@@ -1,4 +1,4 @@
-# link.m4 serial 9
+# link.m4 serial 10
 dnl Copyright (C) 2009-2018 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -39,10 +39,12 @@ AC_DEFUN([gl_FUNC_LINK],
            ]])],
          [gl_cv_func_link_works=yes], [gl_cv_func_link_works=no],
          [case "$host_os" in
-                           # Guess yes on glibc systems.
-            *-gnu* | gnu*) gl_cv_func_link_works="guessing yes" ;;
-                           # If we don't know, assume the worst.
-            *)             gl_cv_func_link_works="guessing no" ;;
+                             # Guess yes on Linux systems.
+            linux-* | linux) gl_cv_func_link_works="guessing yes" ;;
+                             # Guess yes on glibc systems.
+            *-gnu* | gnu*)   gl_cv_func_link_works="guessing yes" ;;
+                             # If we don't know, assume the worst.
+            *)               gl_cv_func_link_works="guessing no" ;;
           esac
          ])
        rm -f conftest.a conftest.b conftest.lnk])
diff --git a/m4/linkat.m4 b/m4/linkat.m4
index 473cacce61..ef601368ea 100644
--- a/m4/linkat.m4
+++ b/m4/linkat.m4
@@ -1,4 +1,4 @@
-# serial 8
+# serial 9
 # See if we need to provide linkat replacement.
 
 dnl Copyright (C) 2009-2018 Free Software Foundation, Inc.
@@ -96,10 +96,14 @@ AC_DEFUN([gl_FUNC_LINKAT],
             ]])],
          [gl_cv_func_linkat_slash=yes],
          [gl_cv_func_linkat_slash=no],
-         [# Guess yes on glibc systems, no otherwise.
+         [
           case "$host_os" in
-            *-gnu* | gnu*) gl_cv_func_linkat_slash="guessing yes";;
-            *)             gl_cv_func_linkat_slash="guessing no";;
+                             # Guess yes on Linux systems.
+            linux-* | linux) gl_cv_func_linkat_slash="guessing yes";;
+                             # Guess yes on glibc systems.
+            *-gnu* | gnu*)   gl_cv_func_linkat_slash="guessing yes";;
+                             # If we don't know, assume the worst.
+            *)               gl_cv_func_linkat_slash="guessing no";;
           esac
          ])
        rm -rf conftest.a conftest.b conftest.c conftest.d conftest.e conftest.s])
diff --git a/m4/lstat.m4 b/m4/lstat.m4
index ac6f143ce7..3694e4ceaf 100644
--- a/m4/lstat.m4
+++ b/m4/lstat.m4
@@ -1,4 +1,4 @@
-# serial 31
+# serial 32
 
 # Copyright (C) 1997-2001, 2003-2018 Free Software Foundation, Inc.
 #
@@ -53,6 +53,9 @@ AC_DEFUN([gl_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK],
        [gl_cv_func_lstat_dereferences_slashed_symlink=yes],
        [gl_cv_func_lstat_dereferences_slashed_symlink=no],
        [case "$host_os" in
+          linux-* | linux)
+            # Guess yes on Linux systems.
+            gl_cv_func_lstat_dereferences_slashed_symlink="guessing yes" ;;
           *-gnu* | gnu*)
             # Guess yes on glibc systems.
             gl_cv_func_lstat_dereferences_slashed_symlink="guessing yes" ;;
diff --git a/m4/mkdir.m4 b/m4/mkdir.m4
index cea85a2eb6..1452999cbf 100644
--- a/m4/mkdir.m4
+++ b/m4/mkdir.m4
@@ -1,4 +1,4 @@
-# serial 13
+# serial 14
 
 # Copyright (C) 2001, 2003-2004, 2006, 2008-2018 Free Software Foundation, Inc.
 # This file is free software; the Free Software Foundation
@@ -23,19 +23,21 @@ AC_DEFUN([gl_FUNC_MKDIR],
       [gl_cv_func_mkdir_trailing_slash_works=yes],
       [gl_cv_func_mkdir_trailing_slash_works=no],
       [case "$host_os" in
-                        # Guess yes on glibc systems.
-         *-gnu* | gnu*) gl_cv_func_mkdir_trailing_slash_works="guessing yes" ;;
-                        # Guess yes on MSVC, no on mingw.
-         mingw*)        AC_EGREP_CPP([Known], [
+                          # Guess yes on Linux systems.
+         linux-* | linux) gl_cv_func_mkdir_trailing_slash_works="guessing yes" ;;
+                          # Guess yes on glibc systems.
+         *-gnu* | gnu*)   gl_cv_func_mkdir_trailing_slash_works="guessing yes" ;;
+                          # Guess yes on MSVC, no on mingw.
+         mingw*)          AC_EGREP_CPP([Known], [
 #ifdef _MSC_VER
  Known
 #endif
-                          ],
-                          [gl_cv_func_mkdir_trailing_slash_works="guessing yes"],
-                          [gl_cv_func_mkdir_trailing_slash_works="guessing no"])
-                        ;;
-                        # If we don't know, assume the worst.
-         *)             gl_cv_func_mkdir_trailing_slash_works="guessing no" ;;
+                            ],
+                            [gl_cv_func_mkdir_trailing_slash_works="guessing yes"],
+                            [gl_cv_func_mkdir_trailing_slash_works="guessing no"])
+                          ;;
+                          # If we don't know, assume the worst.
+         *)               gl_cv_func_mkdir_trailing_slash_works="guessing no" ;;
        esac
       ])
     rm -rf conftest.dir
diff --git a/m4/mkfifo.m4 b/m4/mkfifo.m4
index 5dda67c389..668e786fcb 100644
--- a/m4/mkfifo.m4
+++ b/m4/mkfifo.m4
@@ -1,4 +1,4 @@
-# serial 6
+# serial 7
 # See if we need to provide mkfifo replacement.
 
 dnl Copyright (C) 2009-2018 Free Software Foundation, Inc.
@@ -50,10 +50,12 @@ AC_DEFUN([gl_FUNC_MKFIFO],
            ]])],
          [gl_cv_func_mkfifo_works=yes], [gl_cv_func_mkfifo_works=no],
          [case "$host_os" in
-                           # Guess yes on glibc systems.
-            *-gnu* | gnu*) gl_cv_func_mkfifo_works="guessing yes" ;;
-                           # If we don't know, assume the worst.
-            *)             gl_cv_func_mkfifo_works="guessing no" ;;
+                             # Guess yes on Linux systems.
+            linux-* | linux) gl_cv_func_mkfifo_works="guessing yes" ;;
+                             # Guess yes on glibc systems.
+            *-gnu* | gnu*)   gl_cv_func_mkfifo_works="guessing yes" ;;
+                             # If we don't know, assume the worst.
+            *)               gl_cv_func_mkfifo_works="guessing no" ;;
           esac
          ])
        rm -f conftest.tmp conftest.lnk])
diff --git a/m4/mknod.m4 b/m4/mknod.m4
index 9af56ded7d..b6397147ec 100644
--- a/m4/mknod.m4
+++ b/m4/mknod.m4
@@ -1,4 +1,4 @@
-# serial 6
+# serial 7
 # See if we need to provide mknod replacement.
 
 dnl Copyright (C) 2009-2018 Free Software Foundation, Inc.
@@ -43,10 +43,12 @@ AC_DEFUN([gl_FUNC_MKNOD],
           fi
           gl_cv_func_mknod_works=no],
          [case "$host_os" in
-                           # Guess yes on glibc systems.
-            *-gnu* | gnu*) gl_cv_func_mknod_works="guessing yes" ;;
-                           # If we don't know, assume the worst.
-            *)             gl_cv_func_mknod_works="guessing no" ;;
+                             # Guess yes on Linux systems.
+            linux-* | linux) gl_cv_func_mknod_works="guessing yes" ;;
+                             # Guess yes on glibc systems.
+            *-gnu* | gnu*)   gl_cv_func_mknod_works="guessing yes" ;;
+                             # If we don't know, assume the worst.
+            *)               gl_cv_func_mknod_works="guessing no" ;;
           esac
          ])
        rm -f conftest.fifo])
diff --git a/m4/pselect.m4 b/m4/pselect.m4
index edf4d82820..5cd1e044fc 100644
--- a/m4/pselect.m4
+++ b/m4/pselect.m4
@@ -1,4 +1,4 @@
-# pselect.m4 serial 6
+# pselect.m4 serial 7
 dnl Copyright (C) 2011-2018 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -51,10 +51,12 @@ AC_DEFUN([gl_FUNC_PSELECT],
       [gl_cv_func_pselect_detects_ebadf=no],
           [
            case "$host_os" in
-                           # Guess yes on glibc systems.
-            *-gnu* | gnu*) gl_cv_func_pselect_detects_ebadf="guessing yes" ;;
-                           # If we don't know, assume the worst.
-            *)             gl_cv_func_pselect_detects_ebadf="guessing no" ;;
+                             # Guess yes on Linux systems.
+            linux-* | linux) gl_cv_func_pselect_detects_ebadf="guessing yes" ;;
+                             # Guess yes on glibc systems.
+            *-gnu* | gnu*)   gl_cv_func_pselect_detects_ebadf="guessing yes" ;;
+                             # If we don't know, assume the worst.
+            *)               gl_cv_func_pselect_detects_ebadf="guessing no" ;;
            esac
           ])
       ])
diff --git a/m4/readlink.m4 b/m4/readlink.m4
index 9d73f5cfa1..4d0ab4836b 100644
--- a/m4/readlink.m4
+++ b/m4/readlink.m4
@@ -1,4 +1,4 @@
-# readlink.m4 serial 13
+# readlink.m4 serial 14
 dnl Copyright (C) 2003, 2007, 2009-2018 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -34,10 +34,12 @@ AC_DEFUN([gl_FUNC_READLINK],
       return readlink ("conftest.lnk2/", buf, sizeof buf) != -1;]])],
          [gl_cv_func_readlink_works=yes], [gl_cv_func_readlink_works=no],
          [case "$host_os" in
-                           # Guess yes on glibc systems.
-            *-gnu* | gnu*) gl_cv_func_readlink_works="guessing yes" ;;
-                           # If we don't know, assume the worst.
-            *)             gl_cv_func_readlink_works="guessing no" ;;
+                             # Guess yes on Linux systems.
+            linux-* | linux) gl_cv_func_readlink_works="guessing yes" ;;
+                             # Guess yes on glibc systems.
+            *-gnu* | gnu*)   gl_cv_func_readlink_works="guessing yes" ;;
+                             # If we don't know, assume the worst.
+            *)               gl_cv_func_readlink_works="guessing no" ;;
           esac
          ])
       rm -f conftest.link conftest.lnk2])
diff --git a/m4/rename.m4 b/m4/rename.m4
index f7fa3bb216..e7ff1bfac3 100644
--- a/m4/rename.m4
+++ b/m4/rename.m4
@@ -1,4 +1,4 @@
-# serial 29
+# serial 30
 
 # Copyright (C) 2001, 2003, 2005-2006, 2009-2018 Free Software Foundation, Inc.
 # This file is free software; the Free Software Foundation
@@ -55,12 +55,14 @@ AC_DEFUN([gl_FUNC_RENAME],
       [gl_cv_func_rename_slash_dst_works=no],
       dnl When crosscompiling, assume rename is broken.
       [case "$host_os" in
-                 # Guess yes on glibc systems.
-         *-gnu*) gl_cv_func_rename_slash_dst_works="guessing yes" ;;
-                 # Guess no on native Windows.
-         mingw*) gl_cv_func_rename_slash_dst_works="guessing no" ;;
-                 # If we don't know, assume the worst.
-         *)      gl_cv_func_rename_slash_dst_works="guessing no" ;;
+                          # Guess yes on Linux systems.
+         linux-* | linux) gl_cv_func_rename_slash_dst_works="guessing yes" ;;
+                          # Guess yes on glibc systems.
+         *-gnu*)          gl_cv_func_rename_slash_dst_works="guessing yes" ;;
+                          # Guess no on native Windows.
+         mingw*)          gl_cv_func_rename_slash_dst_works="guessing no" ;;
+                          # If we don't know, assume the worst.
+         *)               gl_cv_func_rename_slash_dst_works="guessing no" ;;
        esac
       ])
     rm -rf conftest.f conftest.f1 conftest.f2 conftest.d1 conftest.d2 conftest.lnk
@@ -109,12 +111,14 @@ AC_DEFUN([gl_FUNC_RENAME],
       [gl_cv_func_rename_slash_src_works=no],
       dnl When crosscompiling, assume rename is broken.
       [case "$host_os" in
-                 # Guess yes on glibc systems.
-         *-gnu*) gl_cv_func_rename_slash_src_works="guessing yes" ;;
-                 # Guess yes on native Windows.
-         mingw*) gl_cv_func_rename_slash_src_works="guessing yes" ;;
-                 # If we don't know, assume the worst.
-         *)      gl_cv_func_rename_slash_src_works="guessing no" ;;
+                          # Guess yes on Linux systems.
+         linux-* | linux) gl_cv_func_rename_slash_src_works="guessing yes" ;;
+                          # Guess yes on glibc systems.
+         *-gnu*)          gl_cv_func_rename_slash_src_works="guessing yes" ;;
+                          # Guess yes on native Windows.
+         mingw*)          gl_cv_func_rename_slash_src_works="guessing yes" ;;
+                          # If we don't know, assume the worst.
+         *)               gl_cv_func_rename_slash_src_works="guessing no" ;;
        esac
       ])
     rm -rf conftest.f conftest.f1 conftest.d1 conftest.d2 conftest.d3 conftest.lnk
@@ -169,12 +173,14 @@ AC_DEFUN([gl_FUNC_RENAME],
            [gl_cv_func_rename_link_works=no],
            dnl When crosscompiling, assume rename is broken.
            [case "$host_os" in
-                      # Guess yes on glibc systems.
-              *-gnu*) gl_cv_func_rename_link_works="guessing yes" ;;
-                      # Guess yes on native Windows.
-              mingw*) gl_cv_func_rename_link_works="guessing yes" ;;
-                      # If we don't know, assume the worst.
-              *)      gl_cv_func_rename_link_works="guessing no" ;;
+                               # Guess yes on Linux systems.
+              linux-* | linux) gl_cv_func_rename_link_works="guessing yes" ;;
+                               # Guess yes on glibc systems.
+              *-gnu*)          gl_cv_func_rename_link_works="guessing yes" ;;
+                               # Guess yes on native Windows.
+              mingw*)          gl_cv_func_rename_link_works="guessing yes" ;;
+                               # If we don't know, assume the worst.
+              *)               gl_cv_func_rename_link_works="guessing no" ;;
             esac
            ])
        else
@@ -220,12 +226,14 @@ AC_DEFUN([gl_FUNC_RENAME],
       [gl_cv_func_rename_dest_works=no],
       dnl When crosscompiling, assume rename is broken.
       [case "$host_os" in
-                 # Guess yes on glibc systems.
-         *-gnu*) gl_cv_func_rename_dest_works="guessing yes" ;;
-                 # Guess no on native Windows.
-         mingw*) gl_cv_func_rename_dest_works="guessing no" ;;
-                 # If we don't know, assume the worst.
-         *)      gl_cv_func_rename_dest_works="guessing no" ;;
+                          # Guess yes on Linux systems.
+         linux-* | linux) gl_cv_func_rename_dest_works="guessing yes" ;;
+                          # Guess yes on glibc systems.
+         *-gnu*)          gl_cv_func_rename_dest_works="guessing yes" ;;
+                          # Guess no on native Windows.
+         mingw*)          gl_cv_func_rename_dest_works="guessing no" ;;
+                          # If we don't know, assume the worst.
+         *)               gl_cv_func_rename_dest_works="guessing no" ;;
        esac
       ])
     rm -rf conftest.f conftest.d1 conftest.d2
diff --git a/m4/rmdir.m4 b/m4/rmdir.m4
index 36c45146f6..a24d845e37 100644
--- a/m4/rmdir.m4
+++ b/m4/rmdir.m4
@@ -1,4 +1,4 @@
-# rmdir.m4 serial 15
+# rmdir.m4 serial 16
 dnl Copyright (C) 2002, 2005, 2009-2018 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -33,12 +33,14 @@ AC_DEFUN([gl_FUNC_RMDIR],
     ]])],
        [gl_cv_func_rmdir_works=yes], [gl_cv_func_rmdir_works=no],
        [case "$host_os" in
-                         # Guess yes on glibc systems.
-          *-gnu* | gnu*) gl_cv_func_rmdir_works="guessing yes" ;;
-                         # Guess no on native Windows.
-          mingw*)        gl_cv_func_rmdir_works="guessing no" ;;
-                         # If we don't know, assume the worst.
-          *)             gl_cv_func_rmdir_works="guessing no" ;;
+                           # Guess yes on Linux systems.
+          linux-* | linux) gl_cv_func_rmdir_works="guessing yes" ;;
+                           # Guess yes on glibc systems.
+          *-gnu* | gnu*)   gl_cv_func_rmdir_works="guessing yes" ;;
+                           # Guess no on native Windows.
+          mingw*)          gl_cv_func_rmdir_works="guessing no" ;;
+                           # If we don't know, assume the worst.
+          *)               gl_cv_func_rmdir_works="guessing no" ;;
         esac
        ])
      rm -rf conftest.dir conftest.file])
diff --git a/m4/select.m4 b/m4/select.m4
index db580378cd..098af8ee7a 100644
--- a/m4/select.m4
+++ b/m4/select.m4
@@ -1,4 +1,4 @@
-# select.m4 serial 9
+# select.m4 serial 10
 dnl Copyright (C) 2009-2018 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -74,10 +74,12 @@ changequote([,])dnl
       [gl_cv_func_select_detects_ebadf=no],
           [
            case "$host_os" in
-                           # Guess yes on glibc systems.
-            *-gnu* | gnu*) gl_cv_func_select_detects_ebadf="guessing yes" ;;
-                           # If we don't know, assume the worst.
-            *)             gl_cv_func_select_detects_ebadf="guessing no" ;;
+                             # Guess yes on Linux systems.
+            linux-* | linux) gl_cv_func_select_detects_ebadf="guessing yes" ;;
+                             # Guess yes on glibc systems.
+            *-gnu* | gnu*)   gl_cv_func_select_detects_ebadf="guessing yes" ;;
+                             # If we don't know, assume the worst.
+            *)               gl_cv_func_select_detects_ebadf="guessing no" ;;
            esac
           ])
       ])
diff --git a/m4/stat.m4 b/m4/stat.m4
index d762cba24e..e8ec3b2b96 100644
--- a/m4/stat.m4
+++ b/m4/stat.m4
@@ -1,4 +1,4 @@
-# serial 14
+# serial 15
 
 # Copyright (C) 2009-2018 Free Software Foundation, Inc.
 #
@@ -43,10 +43,12 @@ AC_DEFUN([gl_FUNC_STAT],
              ]])],
            [gl_cv_func_stat_file_slash=yes], [gl_cv_func_stat_file_slash=no],
            [case "$host_os" in
-                             # Guess yes on glibc systems.
-              *-gnu* | gnu*) gl_cv_func_stat_file_slash="guessing yes" ;;
-                             # If we don't know, assume the worst.
-              *)             gl_cv_func_stat_file_slash="guessing no" ;;
+                               # Guess yes on Linux systems.
+              linux-* | linux) gl_cv_func_stat_file_slash="guessing yes" ;;
+                               # Guess yes on glibc systems.
+              *-gnu* | gnu*)   gl_cv_func_stat_file_slash="guessing yes" ;;
+                               # If we don't know, assume the worst.
+              *)               gl_cv_func_stat_file_slash="guessing no" ;;
             esac
            ])
          rm -f conftest.tmp conftest.lnk])
diff --git a/m4/symlink.m4 b/m4/symlink.m4
index a452f7cc3a..afaa941744 100644
--- a/m4/symlink.m4
+++ b/m4/symlink.m4
@@ -1,4 +1,4 @@
-# serial 7
+# serial 8
 # See if we need to provide symlink replacement.
 
 dnl Copyright (C) 2009-2018 Free Software Foundation, Inc.
@@ -36,10 +36,12 @@ AC_DEFUN([gl_FUNC_SYMLINK],
            ]])],
          [gl_cv_func_symlink_works=yes], [gl_cv_func_symlink_works=no],
          [case "$host_os" in
-                           # Guess yes on glibc systems.
-            *-gnu* | gnu*) gl_cv_func_symlink_works="guessing yes" ;;
-                           # If we don't know, assume the worst.
-            *)             gl_cv_func_symlink_works="guessing no" ;;
+                             # Guess yes on Linux systems.
+            linux-* | linux) gl_cv_func_symlink_works="guessing yes" ;;
+                             # Guess yes on glibc systems.
+            *-gnu* | gnu*)   gl_cv_func_symlink_works="guessing yes" ;;
+                             # If we don't know, assume the worst.
+            *)               gl_cv_func_symlink_works="guessing no" ;;
           esac
          ])
       rm -f conftest.f conftest.link conftest.lnk2])
diff --git a/m4/symlinkat.m4 b/m4/symlinkat.m4
index 0713c18e8c..d69228af70 100644
--- a/m4/symlinkat.m4
+++ b/m4/symlinkat.m4
@@ -1,4 +1,4 @@
-# serial 8
+# serial 9
 # See if we need to provide symlinkat replacement.
 
 dnl Copyright (C) 2009-2018 Free Software Foundation, Inc.
@@ -37,10 +37,12 @@ AC_DEFUN([gl_FUNC_SYMLINKAT],
          [gl_cv_func_symlinkat_works=yes],
          [gl_cv_func_symlinkat_works=no],
          [case "$host_os" in
-                           # Guess yes on glibc systems.
-            *-gnu* | gnu*) gl_cv_func_symlinkat_works="guessing yes" ;;
-                           # If we don't know, assume the worst.
-            *)             gl_cv_func_symlinkat_works="guessing no" ;;
+                             # Guess yes on Linux systems.
+            linux-* | linux) gl_cv_func_symlinkat_works="guessing yes" ;;
+                             # Guess yes on glibc systems.
+            *-gnu* | gnu*)   gl_cv_func_symlinkat_works="guessing yes" ;;
+                             # If we don't know, assume the worst.
+            *)               gl_cv_func_symlinkat_works="guessing no" ;;
           esac
          ])
       rm -f conftest.f conftest.link conftest.lnk2])
diff --git a/m4/unlink.m4 b/m4/unlink.m4
index 73172e84d2..6faaa5cd2e 100644
--- a/m4/unlink.m4
+++ b/m4/unlink.m4
@@ -1,4 +1,4 @@
-# unlink.m4 serial 12
+# unlink.m4 serial 13
 dnl Copyright (C) 2009-2018 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -43,12 +43,14 @@ AC_DEFUN([gl_FUNC_UNLINK],
       [gl_cv_func_unlink_honors_slashes=yes],
       [gl_cv_func_unlink_honors_slashes=no],
       [case "$host_os" in
-                 # Guess yes on glibc systems.
-         *-gnu*) gl_cv_func_unlink_honors_slashes="guessing yes" ;;
-                 # Guess no on native Windows.
-         mingw*) gl_cv_func_unlink_honors_slashes="guessing no" ;;
-                 # If we don't know, assume the worst.
-         *)      gl_cv_func_unlink_honors_slashes="guessing no" ;;
+                          # Guess yes on Linux systems.
+         linux-* | linux) gl_cv_func_unlink_honors_slashes="guessing yes" ;;
+                          # Guess yes on glibc systems.
+         *-gnu*)          gl_cv_func_unlink_honors_slashes="guessing yes" ;;
+                          # Guess no on native Windows.
+         mingw*)          gl_cv_func_unlink_honors_slashes="guessing no" ;;
+                          # If we don't know, assume the worst.
+         *)               gl_cv_func_unlink_honors_slashes="guessing no" ;;
        esac
       ])
      rm -f conftest.file conftest.lnk])
diff --git a/m4/utimens.m4 b/m4/utimens.m4
index 16798a0ad1..9a4db07a3d 100644
--- a/m4/utimens.m4
+++ b/m4/utimens.m4
@@ -3,7 +3,7 @@ dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
-dnl serial 8
+dnl serial 9
 
 AC_DEFUN([gl_UTIMENS],
 [
@@ -31,10 +31,12 @@ AC_DEFUN([gl_UTIMENS],
         [gl_cv_func_futimesat_works=yes],
         [gl_cv_func_futimesat_works=no],
         [case "$host_os" in
-                   # Guess yes on glibc systems.
-           *-gnu*) gl_cv_func_futimesat_works="guessing yes" ;;
-                   # If we don't know, assume the worst.
-           *)      gl_cv_func_futimesat_works="guessing no" ;;
+                            # Guess yes on Linux systems.
+           linux-* | linux) gl_cv_func_futimesat_works="guessing yes" ;;
+                            # Guess yes on glibc systems.
+           *-gnu*)          gl_cv_func_futimesat_works="guessing yes" ;;
+                            # If we don't know, assume the worst.
+           *)               gl_cv_func_futimesat_works="guessing no" ;;
          esac
         ])
       rm -f conftest.file])