testsuite: Fix up modules.exp [PR108899]

testsuite: Fix up modules.exp [PR108899]

On Wed, Feb 22, 2023 at 02:33:42PM -0300, Alexandre Oliva via Gcc-patches wrote:
> When a multi-source module is found to be unsupported, we fail
> module_cmi_p and subsequent sources.  Override proc unsupported to
> mark the result in module_do, and test it to skip module_cmp_p and
> subsequent related tests.
>
> for  gcc/testsuite/ChangeLog
>
>       * g++.dg/modules/modules.exp: Override unsupported to update
>       module_do, and test it after dg-test.

This patch breaks testing with more than one set of options in
target board, like
make check-g++ RUNTESTFLAGS='--target_board=unix\{-m32,-m64\} modules.exp'
yields:
...
                 === g++ Summary for unix/-m32 ===

 # of expected passes            7217
 # of unexpected failures        1
 # of expected failures          18
 # of unsupported tests          2
 Running target unix/-m64
...
 ERROR: tcl error sourcing /home/jakub/src/gcc/gcc/testsuite/g++.dg/modules/modules.exp.
 ERROR: tcl error code TCL OPERATION RENAME TARGET_EXISTS
 ERROR: can't rename to "saved-unsupported": command already exists
     while executing
 "rename unsupported saved-unsupported"
     (file "/home/jakub/src/gcc/gcc/testsuite/g++.dg/modules/modules.exp" line 322)
     invoked from within
 "source /home/jakub/src/gcc/gcc/testsuite/g++.dg/modules/modules.exp"
     ("uplevel" body line 1)
     invoked from within
 "uplevel #0 source /home/jakub/src/gcc/gcc/testsuite/g++.dg/modules/modules.exp"
     invoked from within
 "catch "uplevel #0 source $test_file_name" msg"

In other spots where we in *.exp files rename some routine, we guard that
and the following patch does that for modules.exp too.

Tested with running
make check-g++ RUNTESTFLAGS='--target_board=unix\{-m32,-m64\} modules.exp'
again which now works properly again.

2023-02-23  Jakub Jelinek  <jakub@redhat.com>

	PR testsuite/108899
	* g++.dg/modules/modules.exp: Only override unsupported if it
	exists and saved-unsupported doesn't.