[testsuite] Fix pr25109.sh on riscv64

On riscv64, I run into:
...
cc main.c no-multifile-prop-dw.S -o no-multifile-prop
no-multifile-prop-dw.S: Assembler messages:
no-multifile-prop-dw.S:25: Error: non-constant .uleb128 is not supported
make: *** [Makefile:99: no-multifile-prop] Error 1
...

Fix this by allowing to fail to build the test-case, and marking it as
unsupported.

2021-02-26  Tom de Vries  <tdevries@suse.de>

	* Makefile (no-multifile-prop): Add target rule.
	* testsuite/dwz.tests/dwz-tests.exp: Require no-multifile-prop for
	pr25109.sh.

---
 Makefile                          | 6 +++++-
 testsuite/dwz.tests/dwz-tests.exp | 3 +++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index d320266..7969490 100644
--- a/Makefile
+++ b/Makefile
@@ -95,9 +95,13 @@ $(TEMP_ASM_FILES): %-dw.S: $(TEST_SRC)/../lib/%.exp
 	  export DEJAGNU=$(DEJAGNU); \
 	  runtest --tool=dwz -srcdir $(srcdir)/testsuite/ lib/$*.exp
 
-$(TEST_EXECS_DWARF_ASM): %: %-dw.S
+$(filter-out no-multifile-prop, $(TEST_EXECS_DWARF_ASM)): %: %-dw.S
 	$(CC) $(TEST_SRC)/main.c $< -o $@
 
+# Fails to compile on riscv64: Error: non-constant .uleb128 is not supported.
+no-multifile-prop: %: %-dw.S
+	$(CC) $(TEST_SRC)/main.c $< -o $@ || true
+
 odr-struct:
 	$(CXX) $(TEST_SRC)/odr.cc $(TEST_SRC)/odr-2.cc -I$(TEST_SRC) -o $@ -g \
 	  -DKIND=struct
diff --git a/testsuite/dwz.tests/dwz-tests.exp b/testsuite/dwz.tests/dwz-tests.exp
index 48c0015..0ad77ea 100644
--- a/testsuite/dwz.tests/dwz-tests.exp
+++ b/testsuite/dwz.tests/dwz-tests.exp
@@ -86,6 +86,9 @@ foreach test $tests {
 	    continue
 	}
     }
+    if { $basename == "pr25109.sh" } {
+	lappend required_execs no-multifile-prop
+    }
 
     set unsupported 0
     foreach required_exec $required_execs {