Don't use ensure_gdb_index with require

This series changes 'require' to take a list of simple predicates.
This patch backs out the one use of 'require' that doesn't conform to
this -- calling ensure_gdb_index.

gdb/testsuite/gdb.base/with-mf.exp

@@ -24,7 +24,10 @@ if {[prepare_for_testing "failed to prepare" $testfile "$srcfile $srcfile2" \
     return -1
 }
 
-require {ensure_gdb_index $binfile} != -1
+if { [ensure_gdb_index $binfile] == -1 } {
+    untested "error adding gdb index"
+    return -1
+}
 
 clean_restart $binfile
 

gdb/testsuite/gdb.dwarf2/gdb-add-index-symlink.exp

@@ -29,7 +29,10 @@ with_test_prefix non-symlink {
 	return -1
     }
 
-    require {ensure_gdb_index $binfile} != -1
+    if { [ensure_gdb_index $binfile] == -1 } {
+	untested "error adding gdb index"
+	return -1
+    }
 }
 
 # Regenerate exec without index.

gdb/testsuite/gdb.dwarf2/gdb-add-index.exp

@@ -27,7 +27,10 @@ if { [prepare_for_testing "failed to prepare" "${testfile}" \
     return -1
 }
 
-require {ensure_gdb_index $binfile} != -1
+if { [ensure_gdb_index $binfile] == -1 } {
+    untested "error adding gdb index"
+    return -1
+}
 
 # Ok, we have a copy of $binfile with an index.
 # Restart gdb and verify the index was used.

gdb/testsuite/gdb.dwarf2/gdb-index-types-dwarf5.exp

@@ -24,7 +24,10 @@ if { [prepare_for_testing "failed to prepare" ${testfile} \
     return -1
 }
 
-require {ensure_gdb_index $binfile} == 1
+if { [ensure_gdb_index $binfile] != 1 } {
+    untested "error adding gdb index"
+    return -1
+}
 
 clean_restart ${binfile}
 

gdb/testsuite/gdb.dwarf2/imported-unit-runto-main.exp

@@ -74,7 +74,10 @@ if { [prepare_for_testing "failed to prepare" ${testfile} \
     return -1
 }
 
-require {ensure_gdb_index $binfile} != -1
+if { [ensure_gdb_index $binfile] == -1 } {
+    untested "error adding gdb index"
+    return -1
+}
 
 clean_restart ${binfile}
 

gdb/testsuite/gdb.rust/dwindex.exp

@@ -26,7 +26,10 @@ if {[prepare_for_testing "failed to prepare" $testfile $srcfile {debug rust}]} {
     return -1
 }
 
-require {ensure_gdb_index $binfile -dwarf-5} != -1
+if {[ensure_gdb_index $binfile -dwarf-5] == -1} {
+    untested "error adding gdb index"
+    return -1
+}
 
 gdb_exit
 gdb_start