Suppress warnings for implicit fallthrough by parsing comments.

Makefile

@@ -26,7 +26,7 @@ uname_S := $(shell sh -c 'echo $(uname_S) | sed s/_.*$$//')
 PROGRAM=ue
 
 CC=gcc
-WARNINGS=-pedantic -Wall -Wextra -Wstrict-prototypes -Wno-unused-parameter
+WARNINGS=-pedantic -Wall -Wextra -Wstrict-prototypes -Wno-unused-parameter -Wimplicit-fallthrough=2
 CFLAGS=-O2 $(WARNINGS)
 #CC=c89 +O3			# HP
 #CFLAGS= -D_HPUX_SOURCE -DSYSV
@@ -130,7 +130,7 @@ depend: ${SRC}
 	$(Q) ${CC} ${CFLAGS} ${DEFINES} -c $*.c
 
 # DO NOT DELETE THIS LINE -- make depend uses it
-# Updated Tue, Aug 13, 2019  7:51:49 AM
+# Updated Mon Nov 25 12:50:00 CST 2019
 
 basic.o: basic.c basic.h retcode.h input.h bind.h mlout.h random.h \
  terminal.h defines.h utf8.h window.h buffer.h line.h

exec.c

@@ -795,6 +795,7 @@ static int dobuf(struct buffer *bp)
                 }
                 /* drop down and act just like !BREAK */
 
+				/* fallthrough */
             case DBREAK:    /* BREAK directive */
                 if (dirnum == DBREAK && execlevel)
                     goto onward;

execute.c

@@ -285,6 +285,8 @@ int execute( int c, int f, int n) {
 
 			break ;
 		}
+
+		/* fallthrough */
 	default:
 		status = linsert( n, c) ;
 	}

search.c

@@ -1542,7 +1542,7 @@ static int cclmake(char **ppatptr, struct magic *mcptr)
 			 */
 		case MC_ESC:
 			pchr = *++patptr;
-			/* falltrhough */
+			/* fallthrough */
 		default:
 			setbit(pchr, bmap);
 			break;