Do check-textrel test using readelf rather than a build-time C program.

scripts/check-textrel.awk

@@ -0,0 +1,41 @@
+# This awk script expects to get command-line files that are each
+# the output of 'readelf -d' on a single shared object.
+# It exits successfully (0) if none contained any TEXTREL markers.
+# It fails (1) if any did contain a TEXTREL marker.
+# It fails (2) if the input did not take the expected form.
+
+BEGIN { result = textrel = sanity = 0 }
+
+function check_one(name) {
+  if (!sanity) {
+    print name ": *** input did not look like readelf -d output";
+    result = 2;
+  } else if (textrel) {
+    print name ": *** text relocations used";
+    result = result ? result : 1;
+  } else {
+    print name ": OK";
+  }
+
+  textrel = sanity = 0;
+}
+
+FILENAME != lastfile {
+  if (lastfile)
+    check_one(lastfile);
+  lastfile = FILENAME;
+}
+
+$1 == "Tag" && $2 == "Type" { sanity = 1 }
+$2 == "(TEXTREL)" { textrel = 1 }
+$2 == "(FLAGS)" {
+  for (i = 3; i <= NF; ++i) {
+    if ($i == "TEXTREL")
+      textrel = 1;
+  }
+}
+
+END {
+  check_one(lastfile);
+  exit(result);
+}