Let's try this. It's BUGGERED.

src/cmd/tbl/tc.c

@@ -0,0 +1,65 @@
+/* tc.c: find character not in table to delimit fields */
+# include "t.h"
+
+void
+choochar(void)
+{
+				/* choose funny characters to delimit fields */
+	int	had[128], ilin, icol, k;
+	char	*s;
+
+	for (icol = 0; icol < 128; icol++)
+		had[icol] = 0;
+	F1 = F2 = 0;
+	for (ilin = 0; ilin < nlin; ilin++) {
+		if (instead[ilin]) 
+			continue;
+		if (fullbot[ilin]) 
+			continue;
+		for (icol = 0; icol < ncol; icol++) {
+			k = ctype(ilin, icol);
+			if (k == 0 || k == '-' || k == '=')
+				continue;
+			s = table[ilin][icol].col;
+			if (point(s))
+				while (*s)
+					had[*s++] = 1;
+			s = table[ilin][icol].rcol;
+			if (point(s))
+				while (*s)
+					had[*s++] = 1;
+		}
+	}
+				/* choose first funny character */
+	for (
+	    s = "\002\003\005\006\007!%&#/?,:;<=>@`^~_{}+-*ABCDEFGHIJKMNOPQRSTUVWXYZabcdefgjkoqrstwxyz"; 
+	    *s; s++) {
+		if (had[*s] == 0) {
+			F1 = *s;
+			had[F1] = 1;
+			break;
+		}
+	}
+				/* choose second funny character */
+	for (
+	    s = "\002\003\005\006\007:_~^`@;,<=>#%&!/?{}+-*ABCDEFGHIJKMNOPQRSTUVWXZabcdefgjkoqrstuwxyz"; 
+	    *s; s++) {
+		if (had[*s] == 0) {
+			F2 = *s;
+			break;
+		}
+	}
+	if (F1 == 0 || F2 == 0)
+		error("couldn't find characters to use for delimiters");
+	return;
+}
+
+
+int
+point(char *s)
+{
+	int	ss = (int)s;
+	return(ss >= 128 || ss < 0);
+}
+
+