Corrected an issue with the limited bitfield dedicated to port numbers;

this limited ports to 16384, which seemed reasonable at the time.
However, the sky130_sram_macro layouts connect power and ground in a
way that when coupled with "extract unique" can generate tens of
thousands of ports and overrun the bit field, showing that automation
can do the unexpected.  The solution was to split out the port number
from the label record as its own 32-bit value.

database/DBundo.c

@@ -434,6 +434,7 @@ typedef  Label labelUE;
 #define  lue_offset lab_offset
 #define  lue_flags  lab_flags
 #define  lue_text   lab_text
+#define  lue_port   lab_port
 
     /*
      * labelSize(n) is the size of a labelUE large enough to hold
@@ -556,7 +557,7 @@ dbUndoLabelForw(up)
     lab = DBPutFontLabel(dbUndoLastCell, &up->lue_rect,
 	up->lue_font, up->lue_size, up->lue_rotate,
 	&up->lue_offset, up->lue_just, up->lue_text,
-	up->lue_type, up->lue_flags);
+	up->lue_type, up->lue_flags, up->lue_port);
     DBWLabelChanged(dbUndoLastCell, lab, DBW_ALLWINDOWS);
 
     /*