ld: testsuite: Fix "PR ld/28138 (build only)" on Solaris

ld: testsuite: Fix "PR ld/28138 (build only)" on Solaris

The

FAIL: PR ld/28138 (build only)

test FAILs on Solaris:

ld/tmpdir/ld/collect-ld: plugin framework: out of file descriptors. Try using fewer objects/archives

ld/tmpdir/ld/collect-ld: cannot find -lgcc: Too many open files
[...]

I found that the test PASSes when using ulimit -n 21 instead of the
current 20.  Looking with strace/truss, on Linux/i686 the following
files are opened:

301543 openat(AT_FDCWD, "tmpdir/pr28138", O_RDWR|O_CREAT|O_TRUNC|O_LARGEFILE, 0666) = 3
301543 openat(AT_FDCWD, "/lib/../lib32/crt1.o", O_RDONLY|O_LARGEFILE) = 4
301543 openat(AT_FDCWD, "/lib/../lib32/crt1.o", O_RDONLY|O_LARGEFILE) = 5
301543 openat(AT_FDCWD, "/lib/../lib32/crti.o", O_RDONLY|O_LARGEFILE) = 5
301543 openat(AT_FDCWD, "/lib/../lib32/crti.o", O_RDONLY|O_LARGEFILE) = 6
301543 openat(AT_FDCWD, "lib/gcc/i686-pc-linux-gnu/12.1.0/crtbegin.o", O_RDONLY|O_LARGEFILE) = 6
301543 openat(AT_FDCWD, "lib/gcc/i686-pc-linux-gnu/12.1.0/crtbegin.o", O_RDONLY|O_LARGEFILE) = 7
301543 openat(AT_FDCWD, "tmpdir/pr28138.o", O_RDONLY|O_LARGEFILE) = 7
301543 openat(AT_FDCWD, "tmpdir/pr28138.o", O_RDONLY|O_LARGEFILE) = 8
301543 openat(AT_FDCWD, "tmpdir/pr28138.a", O_RDONLY|O_LARGEFILE) = 8
301543 openat(AT_FDCWD, "tmpdir/pr28138.a", O_RDONLY|O_LARGEFILE) = 9
301543 openat(AT_FDCWD, "tmpdir/pr28138-7.o", O_RDONLY|O_LARGEFILE) = 9
301543 openat(AT_FDCWD, "tmpdir/pr28138-7.o", O_RDONLY|O_LARGEFILE) = 10
301543 openat(AT_FDCWD, "tmpdir/pr28138-6.o", O_RDONLY|O_LARGEFILE) = 10
301543 openat(AT_FDCWD, "tmpdir/pr28138-6.o", O_RDONLY|O_LARGEFILE) = 11
301543 openat(AT_FDCWD, "tmpdir/pr28138-5.o", O_RDONLY|O_LARGEFILE) = 11
301543 openat(AT_FDCWD, "tmpdir/pr28138-5.o", O_RDONLY|O_LARGEFILE) = 12
301543 openat(AT_FDCWD, "tmpdir/pr28138-4.o", O_RDONLY|O_LARGEFILE) = 12
301543 openat(AT_FDCWD, "tmpdir/pr28138-4.o", O_RDONLY|O_LARGEFILE) = 13
301543 openat(AT_FDCWD, "tmpdir/pr28138-3.o", O_RDONLY|O_LARGEFILE) = 13
301543 openat(AT_FDCWD, "tmpdir/pr28138-3.o", O_RDONLY|O_LARGEFILE) = 3
301543 openat(AT_FDCWD, "tmpdir/pr28138-2.o", O_RDONLY|O_LARGEFILE) = 3
301543 openat(AT_FDCWD, "tmpdir/pr28138-2.o", O_RDONLY|O_LARGEFILE) = 4
301543 openat(AT_FDCWD, "tmpdir/pr28138-1.o", O_RDONLY|O_LARGEFILE) = 4
301543 openat(AT_FDCWD, "tmpdir/pr28138-1.o", O_RDONLY|O_LARGEFILE) = 5

while on Solaris/i386 there are a couple more:

27726:	openat64(AT_FDCWD, "tmpdir/pr28138", O_RDWR|O_CREAT|O_TRUNC, 0666) = 4
27726:	openat64(AT_FDCWD, "/usr/lib/crt1.o", O_RDONLY)	= 5
27726:	openat64(AT_FDCWD, "/usr/lib/crt1.o", O_RDONLY)	= 6
27726:	openat64(AT_FDCWD, "lib/gcc/i386-pc-solaris2.11/14.2.0/crtp.o", O_RDONLY) = 6
27726:	openat64(AT_FDCWD, "lib/gcc/i386-pc-solaris2.11/14.2.0/crtp.o", O_RDONLY) = 7
27726:	openat64(AT_FDCWD, "/usr/lib/crti.o", O_RDONLY)	= 7
27726:	openat64(AT_FDCWD, "/usr/lib/crti.o", O_RDONLY)	= 8
27726:	openat64(AT_FDCWD, "/usr/lib/values-Xa.o", O_RDONLY) = 8
27726:	openat64(AT_FDCWD, "/usr/lib/values-Xa.o", O_RDONLY) = 9
27726:	openat64(AT_FDCWD, "/usr/lib/values-xpg6.o", O_RDONLY) = 9
27726:	openat64(AT_FDCWD, "/usr/lib/values-xpg6.o", O_RDONLY) = 10
27726:	openat64(AT_FDCWD, "lib/gcc/i386-pc-solaris2.11/14.2.0/crtbegin.o", O_RDONLY) = 10
27726:	openat64(AT_FDCWD, "lib/gcc/i386-pc-solaris2.11/14.2.0/crtbegin.o", O_RDONLY) = 11
27726:	openat64(AT_FDCWD, "tmpdir/pr28138.o", O_RDONLY) = 11
27726:	openat64(AT_FDCWD, "tmpdir/pr28138.o", O_RDONLY) = 12
27726:	openat64(AT_FDCWD, "tmpdir/pr28138.a", O_RDONLY) = 12
27726:	openat64(AT_FDCWD, "tmpdir/pr28138.a", O_RDONLY) = 13
27726:	openat64(AT_FDCWD, "tmpdir/pr28138-7.o", O_RDONLY) = 13
27726:	openat64(AT_FDCWD, "tmpdir/pr28138-7.o", O_RDONLY) = 14
27726:	openat64(AT_FDCWD, "tmpdir/pr28138-6.o", O_RDONLY) = 14
27726:	openat64(AT_FDCWD, "tmpdir/pr28138-6.o", O_RDONLY) = 15
27726:	openat64(AT_FDCWD, "tmpdir/pr28138-5.o", O_RDONLY) = 15
27726:	openat64(AT_FDCWD, "tmpdir/pr28138-5.o", O_RDONLY) = 16
27726:	openat64(AT_FDCWD, "tmpdir/pr28138-4.o", O_RDONLY) = 16
27726:	openat64(AT_FDCWD, "tmpdir/pr28138-4.o", O_RDONLY) = 17
27726:	openat64(AT_FDCWD, "tmpdir/pr28138-3.o", O_RDONLY) = 17
27726:	openat64(AT_FDCWD, "tmpdir/pr28138-3.o", O_RDONLY) = 18
27726:	openat64(AT_FDCWD, "tmpdir/pr28138-2.o", O_RDONLY) = 18
27726:	openat64(AT_FDCWD, "tmpdir/pr28138-2.o", O_RDONLY) = 19
27726:	openat64(AT_FDCWD, "tmpdir/pr28138-1.o", O_RDONLY) = 19
27726:	openat64(AT_FDCWD, "tmpdir/pr28138-1.o", O_RDONLY) Err#24 EMFILE

While it seems weird that the same files are opened twice for reading,
it's no wonder that 20 fds aren't enough on Solaris.

To avoid this, I've raised the limit to 25, hoping that this will be
enough on more targets.

Tested on i386-pc-solaris2.11 and i686-pc-linux-gnu.

2025-07-25  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>

	ld:
	* testsuite/ld-plugin/lto.exp (PR ld/28138 test): Raise fd limit
	to 25.