[bug-gnulib] AC_FUNC_GETMNTENT problem on UNICOS

[Mark D. Baushke]

The autoconf AC_FUNC_GETMNTENT seems to assume that adding -lsun
is always desirable. This is NOT true on UNICOS where the getmntent
function resides in the C library and no -lsun library exists.

The findutils project has been jumping thru hoops to avoid using
AC_FUNC_GETMNTENT to try not to add LIBS=-lsun to the generated Makefile
files and most recently has run into problems with GNULIB using this
macro in their m4/ls-mntd-fs.m4 file.

I believe that a simple check to see if the function is available in the
default library set is reasonable.

I have attached a patch for autoconf-2.59 for this.

As it may be some time until AUTOCONF delivers a new release, I have
attached a patch to GNULIB's m4/ls-mntd-fs.m4 file as well that will
work around the problem until a new AUTOCONF is available.

        -- Mark

Index: autoconf-2.59/lib/autoconf/functions.m4
--- autoconf-2.59/lib/autoconf/functions.m4~    2003-10-27 03:13:42.000000000 
-0800
+++ autoconf-2.59/lib/autoconf/functions.m4     2004-12-06 09:32:08.546246524 
-0800
@@ -771,9 +771,11 @@ AU_ALIAS([AC_GETLOADAVG], [AC_FUNC_GETLO
 AN_FUNCTION([getmntent], [AC_FUNC_GETMNTENT])
 AC_DEFUN([AC_FUNC_GETMNTENT],
 [# getmntent is in -lsun on Irix 4, -lseq on Dynix/PTX, -lgen on Unixware.
-AC_CHECK_LIB(sun, getmntent, LIBS="-lsun $LIBS",
-  [AC_CHECK_LIB(seq, getmntent, LIBS="-lseq $LIBS",
-    [AC_CHECK_LIB(gen, getmntent, LIBS="-lgen $LIBS")])])
+# -lsun does NOT exist on UNICOS 9 where the C library has the function.
+AC_CHECK_FUNC(getmntent, [],
+  [AC_CHECK_LIB(sun, getmntent, LIBS="-lsun $LIBS",
+    [AC_CHECK_LIB(seq, getmntent, LIBS="-lseq $LIBS",
+      [AC_CHECK_LIB(gen, getmntent, LIBS="-lgen $LIBS")])])])
 AC_CHECK_FUNCS(getmntent)
 ])
 
Index: m4/ls-mntd-fs.m4
===================================================================
RCS file: /cvsroot/gnulib/gnulib/m4/ls-mntd-fs.m4,v
retrieving revision 1.28
diff -u -p -u -p -r1.28 ls-mntd-fs.m4
--- ls-mntd-fs.m4       7 Aug 2004 00:09:39 -0000       1.28
+++ ls-mntd-fs.m4       6 Dec 2004 17:44:45 -0000
@@ -64,7 +64,10 @@ ac_list_mounted_fs=

 # If the getmntent function is available but not in the standard library,
 # make sure LIBS contains -lsun (on Irix4) or -lseq (on PTX).
-AC_FUNC_GETMNTENT
+# However, AC_FUNC_GETMNTENT will introduce a -lsun even if getmntent is
+# in the C library, for example on UNICOS which does not have a -lsun
+# library.
+AC_CHECK_FUNC(getmntent, [], [AC_FUNC_GETMNTENT])

 # This test must precede the ones for getmntent because Unicos-9 is
 # reported to have the getmntent function, but its support is incompatible