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.

2 files changed, 16 insertions, 5 deletions

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));