build: port to AIX

Problems reported by Michael Felt, and and part of this fix taken
from code suggested by Pádraig Brady in:
http://bugs.gnu.org/20733#112
* configure.ac (stdbuf_supported): Check for warnings, and
for -fPIC and -shared, for AIX.
* src/stat.c (STRUCT_STATVFS): Define to struct statvfs64 if
STATFS is statvfs64.
* src/sync.c (sync_arg) [_AIX]: Open in write mode,
since AIX fsync doesn't work on read-only file descriptors.
* tests/misc/wc-parallel.sh: Skip test if xargs -P does not work.

4 files changed, 34 insertions, 9 deletions

diff --git a/configure.ac b/configure.ac
index c1599831c..a50992d04 100644
--- a/configure.ac
+++ b/configure.ac
@@ -454,8 +454,17 @@ if test $gl_cv_list_mounted_fs = yes && test $gl_cv_fs_space = yes; then
   gl_ADD_PROG([optional_bin_progs], [df])
 fi
 
-AC_MSG_CHECKING([whether this is system supports stdbuf])
-AC_COMPILE_IFELSE(
+ac_save_CFLAGS=$CFLAGS
+ac_save_LDFLAGS=$LDFLAGS
+# Detect warnings about ignored "constructor" attributes.
+gl_WARN_ADD([-Werror], [CFLAGS])
+gl_WARN_ADD([-errwarn], [CFLAGS])
+# Put this message here, after gl_WARN_ADD's chatter.
+AC_MSG_CHECKING([whether this system supports stdbuf])
+CFLAGS="-fPIC $CFLAGS"
+LDFLAGS="-shared $LDFLAGS"
+stdbuf_supported=no
+AC_LINK_IFELSE(
   [AC_LANG_PROGRAM([[
     static int stdbuf = 0;
 
@@ -470,12 +479,13 @@ AC_COMPILE_IFELSE(
     }]],[[
     return !(stdbuf == 1);]])
   ],
-  [stdbuf_supported=yes],
-  [stdbuf_supported=no])
+  [stdbuf_supported=yes])
 AC_MSG_RESULT([$stdbuf_supported])
 if test "$stdbuf_supported" = "yes" && test -z "$EXEEXT"; then
   gl_ADD_PROG([optional_bin_progs], [stdbuf])
 fi
+CFLAGS=$ac_save_CFLAGS
+LDFLAGS=$ac_save_LDFLAGS
 
 ############################################################################
 
diff --git a/src/stat.c b/src/stat.c
index 4b5aff71f..6d2366539 100644
--- a/src/stat.c
+++ b/src/stat.c
@@ -74,15 +74,16 @@
 #include "xvasprintf.h"
 
 #if USE_STATVFS
-# define STRUCT_STATVFS struct statvfs
 # define STRUCT_STATXFS_F_FSID_IS_INTEGER STRUCT_STATVFS_F_FSID_IS_INTEGER
 # define HAVE_STRUCT_STATXFS_F_TYPE HAVE_STRUCT_STATVFS_F_TYPE
 # if HAVE_STRUCT_STATVFS_F_NAMEMAX
 #  define SB_F_NAMEMAX(S) ((S)->f_namemax)
 # endif
 # if ! STAT_STATVFS && STAT_STATVFS64
+#  define STRUCT_STATVFS struct statvfs64
 #  define STATFS statvfs64
 # else
+#  define STRUCT_STATVFS struct statvfs
 #  define STATFS statvfs
 # endif
 # define STATFS_FRSIZE(S) ((S)->f_frsize)
diff --git a/src/sync.c b/src/sync.c
index 85d77c092..5e1dbb8c6 100644
--- a/src/sync.c
+++ b/src/sync.c
@@ -91,24 +91,34 @@ static bool
 sync_arg (enum sync_mode mode, char const *file)
 {
   bool ret = true;
+  int open_flags = O_RDONLY | O_NONBLOCK;
   int fd;
 
+#ifdef _AIX
+  /* AIX 7.1 fsync requires write access to file.  */
+  if (mode == MODE_FILE)
+    open_flags = O_WRONLY | O_NONBLOCK;
+#endif
+
   /* Note O_PATH might be supported with syncfs(),
      though as of Linux 3.18 is not.  */
-  if ((fd = open (file, O_RDONLY | O_NONBLOCK)) < 0)
+  fd = open (file, open_flags);
+  if (fd < 0)
     {
       /* Use the O_RDONLY errno, which is significant
          with directories for example.  */
       int rd_errno = errno;
-      if ((fd = open (file, O_WRONLY | O_NONBLOCK)) < 0)
+      if (open_flags != (O_WRONLY | O_NONBLOCK))
+        fd = open (file, O_WRONLY | O_NONBLOCK);
+      if (fd < 0)
         error (0, rd_errno, _("error opening %s"), quote (file));
       return false;
     }
 
   /* We used O_NONBLOCK above to not hang with fifos,
      so reset that here.  */
-  int fdflags;
-  if ((fdflags = fcntl (fd, F_GETFL)) == -1
+  int fdflags = fcntl (fd, F_GETFL);
+  if (fdflags == -1
       || fcntl (fd, F_SETFL, fdflags & ~O_NONBLOCK) < 0)
     {
       error (0, errno, _("couldn't reset non-blocking mode %s"), quote (file));
diff --git a/tests/misc/wc-parallel.sh b/tests/misc/wc-parallel.sh
index 2d1e9f405..98c36b9fa 100755
--- a/tests/misc/wc-parallel.sh
+++ b/tests/misc/wc-parallel.sh
@@ -20,6 +20,10 @@
 . "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
 print_ver_ wc
 
+if xargs -P2 </dev/null >/dev/null 2>&1
+  skip_ 'xargs -P is required'
+fi
+
 (mkdir tmp && cd tmp && seq 2000 | xargs touch)
 
 # This will output at least 16KiB per process