[libxml2] Fix compiler warnings in fuzzing code

[Nick Wellnhofer <nwellnhof src gnome org>]

commit d0ab5c4fe6218ebe49dc20ae53420e79d5ce5aad
Author: Nick Wellnhofer <wellnhofer aevum de>
Date:   Fri Sep 2 17:47:48 2022 +0200

    Fix compiler warnings in fuzzing code

 fuzz/genSeed.c    | 17 ++++++++----
 fuzz/html.c       |  2 +-
 fuzz/regexp.c     |  3 +--
 fuzz/testFuzzer.c | 78 ++++++++++++++++++++++++++++++++-----------------------
 4 files changed, 59 insertions(+), 41 deletions(-)
---
diff --git a/fuzz/genSeed.c b/fuzz/genSeed.c
index 01f0656b..dc1c1449 100644
--- a/fuzz/genSeed.c
+++ b/fuzz/genSeed.c
@@ -43,6 +43,8 @@ static struct {
     char cwd[PATH_SIZE];
 } globalData;
 
+#if defined(HAVE_SCHEMA_FUZZER) || \
+    defined(HAVE_XML_FUZZER)
 /*
  * A custom entity loader that writes all external DTDs or entities to a
  * single file in the format expected by xmlFuzzEntityLoader.
@@ -94,13 +96,14 @@ fuzzRecorderInit(FILE *out) {
 }
 
 static void
-fuzzRecorderCleanup() {
+fuzzRecorderCleanup(void) {
     xmlSetExternalEntityLoader(globalData.oldLoader);
     xmlHashFree(globalData.entities, xmlHashDefaultDeallocator);
     globalData.out = NULL;
     globalData.entities = NULL;
     globalData.oldLoader = NULL;
 }
+#endif
 
 #ifdef HAVE_XML_FUZZER
 static int
@@ -169,11 +172,15 @@ processSchema(const char *docFile, FILE *out) {
 }
 #endif
 
+#if defined(HAVE_HTML_FUZZER) || \
+    defined(HAVE_SCHEMA_FUZZER) || \
+    defined(HAVE_XML_FUZZER)
 static int
 processPattern(const char *pattern) {
     glob_t globbuf;
     int ret = 0;
-    int res, i;
+    int res;
+    size_t i;
 
     res = glob(pattern, 0, NULL, &globbuf);
     if (res == GLOB_NOMATCH)
@@ -245,6 +252,7 @@ error:
     globfree(&globbuf);
     return(ret);
 }
+#endif
 
 #ifdef HAVE_XPATH_FUZZER
 static int
@@ -282,7 +290,7 @@ processXPath(const char *testDir, const char *prefix, const char *name,
             continue;
         }
 
-        while (fgets(expr, EXPR_SIZE, in) > 0) {
+        while (fgets(expr, EXPR_SIZE, in) != NULL) {
             char outPath[PATH_SIZE];
             FILE *out;
             int j;
@@ -328,7 +336,7 @@ processXPath(const char *testDir, const char *prefix, const char *name,
     return(ret);
 }
 
-int
+static int
 processXPathDir(const char *testDir) {
     char pattern[PATH_SIZE];
     glob_t globbuf;
@@ -379,7 +387,6 @@ main(int argc, const char **argv) {
     mainFunc processArg = NULL;
     const char *fuzzer;
     int ret = 0;
-    int xpath = 0;
     int i;
 
     if (argc < 3) {
diff --git a/fuzz/html.c b/fuzz/html.c
index 116b3df3..ecc6f7a6 100644
--- a/fuzz/html.c
+++ b/fuzz/html.c
@@ -29,7 +29,7 @@ LLVMFuzzerTestOneInput(const char *data, size_t size) {
     xmlOutputBufferPtr out;
     const char *docBuffer;
     size_t docSize, consumed, chunkSize;
-    int opts, outSize;
+    int opts;
 
     xmlFuzzDataInit(data, size);
     opts = xmlFuzzReadInt();
diff --git a/fuzz/regexp.c b/fuzz/regexp.c
index af1210aa..a0b084a2 100644
--- a/fuzz/regexp.c
+++ b/fuzz/regexp.c
@@ -19,12 +19,11 @@ int
 LLVMFuzzerTestOneInput(const char *data, size_t size) {
     xmlRegexpPtr regexp;
     char *str[2] = { NULL, NULL };
-    size_t numStrings;
 
     if (size > 200)
         return(0);
 
-    numStrings = xmlFuzzExtractStrings(data, size, str, 2);
+    xmlFuzzExtractStrings(data, size, str, 2);
 
     /* CUR_SCHAR doesn't handle invalid UTF-8 and may cause infinite loops. */
     if (xmlCheckUTF8(BAD_CAST str[0]) != 0) {
diff --git a/fuzz/testFuzzer.c b/fuzz/testFuzzer.c
index b0c7ffbc..d14b29be 100644
--- a/fuzz/testFuzzer.c
+++ b/fuzz/testFuzzer.c
@@ -13,51 +13,63 @@
 #include "fuzz.h"
 
 #ifdef HAVE_HTML_FUZZER
-  #define LLVMFuzzerInitialize fuzzHtmlInit
-  #define LLVMFuzzerTestOneInput fuzzHtml
-  #include "html.c"
-  #undef LLVMFuzzerInitialize
-  #undef LLVMFuzzerTestOneInput
+int fuzzHtmlInit(int *argc, char ***argv);
+int fuzzHtml(const char *data, size_t size);
+#define LLVMFuzzerInitialize fuzzHtmlInit
+#define LLVMFuzzerTestOneInput fuzzHtml
+#include "html.c"
+#undef LLVMFuzzerInitialize
+#undef LLVMFuzzerTestOneInput
 #endif
 
 #ifdef HAVE_REGEXP_FUZZER
-  #define LLVMFuzzerInitialize fuzzRegexpInit
-  #define LLVMFuzzerTestOneInput fuzzRegexp
-  #include "regexp.c"
-  #undef LLVMFuzzerInitialize
-  #undef LLVMFuzzerTestOneInput
+int fuzzRegexpInit(int *argc, char ***argv);
+int fuzzRegexp(const char *data, size_t size);
+#define LLVMFuzzerInitialize fuzzRegexpInit
+#define LLVMFuzzerTestOneInput fuzzRegexp
+#include "regexp.c"
+#undef LLVMFuzzerInitialize
+#undef LLVMFuzzerTestOneInput
 #endif
 
 #ifdef HAVE_SCHEMA_FUZZER
-  #define LLVMFuzzerInitialize fuzzSchemaInit
-  #define LLVMFuzzerTestOneInput fuzzSchema
-  #include "schema.c"
-  #undef LLVMFuzzerInitialize
-  #undef LLVMFuzzerTestOneInput
+int fuzzSchemaInit(int *argc, char ***argv);
+int fuzzSchema(const char *data, size_t size);
+#define LLVMFuzzerInitialize fuzzSchemaInit
+#define LLVMFuzzerTestOneInput fuzzSchema
+#include "schema.c"
+#undef LLVMFuzzerInitialize
+#undef LLVMFuzzerTestOneInput
 #endif
 
 #ifdef HAVE_URI_FUZZER
-  #define LLVMFuzzerInitialize fuzzUriInit
-  #define LLVMFuzzerTestOneInput fuzzUri
-  #include "uri.c"
-  #undef LLVMFuzzerInitialize
-  #undef LLVMFuzzerTestOneInput
+int fuzzUriInit(int *argc, char ***argv);
+int fuzzUri(const char *data, size_t size);
+#define LLVMFuzzerInitialize fuzzUriInit
+#define LLVMFuzzerTestOneInput fuzzUri
+#include "uri.c"
+#undef LLVMFuzzerInitialize
+#undef LLVMFuzzerTestOneInput
 #endif
 
 #ifdef HAVE_XML_FUZZER
-  #define LLVMFuzzerInitialize fuzzXmlInit
-  #define LLVMFuzzerTestOneInput fuzzXml
-  #include "xml.c"
-  #undef LLVMFuzzerInitialize
-  #undef LLVMFuzzerTestOneInput
+int fuzzXmlInit(int *argc, char ***argv);
+int fuzzXml(const char *data, size_t size);
+#define LLVMFuzzerInitialize fuzzXmlInit
+#define LLVMFuzzerTestOneInput fuzzXml
+#include "xml.c"
+#undef LLVMFuzzerInitialize
+#undef LLVMFuzzerTestOneInput
 #endif
 
 #ifdef HAVE_XPATH_FUZZER
-  #define LLVMFuzzerInitialize fuzzXPathInit
-  #define LLVMFuzzerTestOneInput fuzzXPath
-  #include "xpath.c"
-  #undef LLVMFuzzerInitialize
-  #undef LLVMFuzzerTestOneInput
+int fuzzXPathInit(int *argc, char ***argv);
+int fuzzXPath(const char *data, size_t size);
+#define LLVMFuzzerInitialize fuzzXPathInit
+#define LLVMFuzzerTestOneInput fuzzXPath
+#include "xpath.c"
+#undef LLVMFuzzerInitialize
+#undef LLVMFuzzerTestOneInput
 #endif
 
 typedef int
@@ -71,7 +83,7 @@ static int
 testFuzzer(initFunc init, fuzzFunc fuzz, const char *pattern) {
     glob_t globbuf;
     int ret = -1;
-    int i;
+    size_t i;
 
     if (glob(pattern, 0, NULL, &globbuf) != 0) {
         fprintf(stderr, "pattern %s matches no files\n", pattern);
@@ -105,7 +117,7 @@ error:
 
 #ifdef HAVE_XML_FUZZER
 static int
-testEntityLoader() {
+testEntityLoader(void) {
     static const char data[] =
         "doc.xml\\\n"
         "<!DOCTYPE doc SYSTEM \"doc.dtd\">\n"
@@ -148,7 +160,7 @@ testEntityLoader() {
 #endif
 
 int
-main() {
+main(void) {
     int ret = 0;
 
 #ifdef HAVE_XML_FUZZER