The Debian packaging of grok is maintained in git, using the merging workflow
described in dgit-maint-merge(7).  There isn't a patch queue that can be
represented as a quilt series.

A detailed breakdown of the changes is available from their canonical
representation - git commits in the packaging repository.  For example, to see
the changes made by the Debian maintainer in the first upload of upstream
version 1.2.3, you could use:

    % git clone https://git.dgit.debian.org/grok
    % cd grok
    % git log --oneline 1.2.3..debian/1.2.3-1 -- . ':!debian'

(If you have dgit, use `dgit clone grok`, rather than plain `git clone`.)

A single combined diff, containing all the changes, follows.

--- grok-1.20110708.1.orig/Makefile
+++ grok-1.20110708.1/Makefile
@@ -162,14 +162,14 @@ cleanver:
 # Binary creation
 grok: LDFLAGS+=-levent
 grok: $(GROKOBJ) conf.tab.o conf.yy.o main.o grok_config.o
-	$(CC) $(LDFLAGS) $^ -o $@
+	$(CC) $^ $(LDFLAGS) -o $@
 
 discogrok: $(GROKOBJ) discover_main.o
-	$(CC) $(LDFLAGS) $^ -o $@
+	$(CC) $^ $(LDFLAGS) -o $@
 
 libgrok.$(LIBSUFFIX): 
 libgrok.$(LIBSUFFIX): $(GROKOBJ) 
-	$(CC) $(LDFLAGS) -fPIC $(DYNLIBFLAG) $(LIBNAMEFLAG) $^ -o $@
+	$(CC) -fPIC $(DYNLIBFLAG) $(LIBNAMEFLAG) $^ $(LDFLAGS)  -o $@
 
 libgrok.$(VERLIBSUFFIX): libgrok.$(LIBSUFFIX);
 	ln -s $< $@
@@ -213,7 +213,7 @@ grok_capture_xdr.h: grok_capture.x
 	rpcgen -h $< -o $@
 
 %.c: %.gperf
-	@if $(GPERF) --version | head -1 | egrep -v '3\.[0-9]+\.[0-9]+' ; then \
+	@if $(GPERF) --version | head -1 | egrep -v '3\.(0\.[3-9]+|[1-9]+)' ; then \
 		echo "We require gperf version >= 3.0.3" ; \
 		exit 1; \
 	fi
--- grok-1.20110708.1.orig/conf.tab.c
+++ grok-1.20110708.1/conf.tab.c
@@ -77,7 +77,7 @@
 #include "grok_input.h"
 #include "grok_matchconf.h"
 
-int yylineno;
+extern int yylineno;
 void yyerror (YYLTYPE *loc, struct config *conf, char const *s) {
   fprintf (stderr, "Syntax error: %s\n", s);
 }
--- grok-1.20110708.1.orig/grok_matchconf_macro.h
+++ grok-1.20110708.1/grok_matchconf_macro.h
@@ -19,6 +19,7 @@ struct strmacro {
 #endif
 
 /* this function is generated by gperf */
-const struct strmacro *patname2macro(const char *str, unsigned int len);
+const struct strmacro *patname2macro (register const char *str, register size_t len);
+
 
 #endif /* _GROK_MATCHCONF_MACRO_ */
--- grok-1.20110708.1.orig/grok_pattern.c
+++ grok-1.20110708.1/grok_pattern.c
@@ -33,9 +33,9 @@ int grok_pattern_add(const grok_t *grok,
 }
 
 int grok_pattern_find(const grok_t *grok, const char *name, size_t name_len,
-                      const char **regexp, size_t *regexp_len) {
+                      const char **regexp, int *regexp_len) {
   TCTREE *patterns = grok->patterns;
-  *regexp = tctreeget(patterns, name, name_len, (int*) regexp_len);
+  *regexp = tctreeget(patterns, name, name_len, regexp_len);
 
   grok_log(grok, LOG_PATTERNS, "Searching for pattern '%s' (%s): %.*s",
            name, *regexp == NULL ? "not found" : "found", *regexp_len, *regexp);
--- grok-1.20110708.1.orig/grok_pattern.h
+++ grok-1.20110708.1/grok_pattern.h
@@ -9,7 +9,7 @@ TCLIST *grok_pattern_name_list(const gro
 int grok_pattern_add(const grok_t *grok, const char *name, size_t name_len,
                       const char *regexp, size_t regexp_len);
 int grok_pattern_find(const grok_t *grok, const char *name, size_t name_len,
-                      const char **regexp, size_t *regexp_len);
+                      const char **regexp, int *regexp_len);
 int grok_patterns_import_from_file(const grok_t *grok, const char *filename);
 int grok_patterns_import_from_string(const grok_t *grok, const char *buffer);
 
--- grok-1.20110708.1.orig/grokre.c
+++ grok-1.20110708.1/grokre.c
@@ -12,8 +12,8 @@
 
 /* global, static variables */
 
-#define CAPTURE_ID_LEN 4
-#define CAPTURE_FORMAT "%04x"
+#define CAPTURE_ID_LEN 5
+#define CAPTURE_FORMAT "_%04x"
 
 /* internal functions */
 static char *grok_pattern_expand(grok_t *grok); //, int offset, int length);
@@ -183,7 +183,7 @@ static char *grok_pattern_expand(grok_t
     int start, end, matchlen;
     const char *pattern_regex;
     int patname_len;
-    size_t regexp_len;
+    int regexp_len;
     int pattern_regex_needs_free = 0;
 
     grok_log(grok, LOG_REGEXPAND, "% 20s: %.*s", "start of loop",
--- grok-1.20110708.1.orig/test/grok_pattern.test.c
+++ grok-1.20110708.1/test/grok_pattern.test.c
@@ -4,7 +4,7 @@
 void test_grok_pattern_add_and_find_work(void) {
   INIT;
   const char *regexp = NULL;
-  size_t len = 0;
+  int len = 0;
 
   grok_pattern_add(&grok, "WORD", 5, "\\w+", 3);
   grok_pattern_add(&grok, "TEST", 5, "TEST", 4);
