filterdiff -z -x '*/debian/*' -x '*/flexint.h' '*/gen.c' -x '*/skel.c' -x '*/scan.c' flex_2.5.35-6.diff.gz
--- flex-2.5.35.orig/flex.skl
+++ flex-2.5.35/flex.skl
@@ -1074,7 +1074,7 @@
 /* This used to be an fputs(), but since the string might contain NUL's,
  * we now use fwrite().
  */
-#define ECHO fwrite( yytext, yyleng, 1, yyout )
+#define ECHO do { if (fwrite( yytext, yyleng, 1, yyout )) {} } while (0)
 %endif
 %if-c++-only C++ definition
 #define ECHO LexerOutput( yytext, yyleng )
@@ -2348,8 +2348,8 @@
 %if-c-only
 /** Setup the input buffer state to scan the given bytes. The next call to yylex() will
  * scan from a @e copy of @a bytes.
- * @param bytes the byte buffer to scan
- * @param len the number of bytes in the buffer pointed to by @a bytes.
+ * @param yybytes the byte buffer to scan
+ * @param _yybytes_len the number of bytes in the buffer pointed to by @a bytes.
  * M4_YY_DOC_PARAM
  * @return the newly allocated buffer state object.
  */
--- flex-2.5.35.orig/tests/test-bison-yylloc/Makefile.am
+++ flex-2.5.35/tests/test-bison-yylloc/Makefile.am
@@ -34,7 +34,7 @@
 
 testname = test-bison-yylloc
 
-scanner.c: $(srcdir)/scanner.l
+scanner.c scanner.h: $(srcdir)/scanner.l
 	$(FLEX) $<
 
 parser.c: $(srcdir)/parser.y
@@ -50,4 +50,5 @@
 	$(CC) -c -o $@ $(AM_CPPFLAGS) $(CPPFLAGS) $(CFLAGS) $<
 
 parser.h: parser.c
-scanner.c main.o: parser.h
+scanner.o: parser.h
+main.o: parser.h scanner.h
--- flex-2.5.35.orig/tests/test-bison-yylval/Makefile.am
+++ flex-2.5.35/tests/test-bison-yylval/Makefile.am
@@ -34,7 +34,7 @@
 
 testname = test-bison-yylval
 
-scanner.c: $(srcdir)/scanner.l
+scanner.c scanner.h: $(srcdir)/scanner.l
 	$(FLEX) $<
 
 parser.c: $(srcdir)/parser.y
@@ -50,4 +50,4 @@
 	$(CC) -c -o $@ $(AM_CPPFLAGS) $(CPPFLAGS) $(CFLAGS) $<
 
 parser.h: parser.c
-main.o: parser.h
+main.o: parser.h scanner.h
--- flex-2.5.35.orig/tests/test-bison-nr/Makefile.am
+++ flex-2.5.35/tests/test-bison-nr/Makefile.am
@@ -34,7 +34,7 @@
 
 testname = test-bison-nr
 
-scanner.c: $(srcdir)/scanner.l
+scanner.c scanner.h: $(srcdir)/scanner.l
 	$(FLEX) $<
 
 parser.c: $(srcdir)/parser.y
@@ -50,4 +50,5 @@
 	$(CC) -c -o $@ $(AM_CPPFLAGS) $(CPPFLAGS) $(CFLAGS) $<
 
 parser.h: parser.c
-scanner.c main.o: parser.h
+scanner.o: parser.h
+main.o: parser.h scanner.h