sky130B missing MINENCLOSEDAREA

Fix a bug in fix_techlefB.py
diff --git a/sky130/custom/scripts/fix_techlefB.py b/sky130/custom/scripts/fix_techlefB.py
index 3fad5bb..e8bccf3 100755
--- a/sky130/custom/scripts/fix_techlefB.py
+++ b/sky130/custom/scripts/fix_techlefB.py
@@ -82,6 +82,7 @@
         pmatch = proprex.match(line)
         rmatch = resrex.match(line)
         lmatch = layerrex.match(line)
+        tmatch = thickrex.match(line)
         if pmatch:
             fixedlines.append(line)
             fixedlines.append('USEMINSPACING OBS OFF ;')
@@ -93,6 +94,8 @@
         elif lmatch:
             fixedlines.append(line)
             curlayer = lmatch.group(1)
+        elif tmatch:
+            thickness_seen = True
         else:
             ematch = edgerex.match(line)
             pmatch = platerex.match(line)