add citation and fix Wstrict-prototypes warning

inst/CITATION

@@ -0,0 +1,14 @@
+bibentry(
+  bibtype  = "Article",
+  title = "vcfpp: a C++ API for rapid processing of the variant call format",
+  author = person("Zilong", "Li"),
+  journal = "Bioinformatics",
+  volume = "40",
+  number = "2",
+  pages = "btae049",
+  year = "2024",
+  month = "01",
+  issn = "1367-4811",
+  abstract = "Given the widespread use of the variant call format (VCF/BCF) coupled with continuous surge in big data, there remains a perpetual demand for fast and flexible methods to manipulate these comprehensive formats across various programming languages.This work presents vcfpp, a C++ API of HTSlib in a single file, providing an intuitive interface to manipulate VCF/BCF files rapidly and safely, in addition to being portable. Moreover, this work introduces the vcfppR package to demonstrate the development of a high-performance R package with vcfpp, allowing for rapid and straightforward variants analyses.vcfpp is available from https://github.com/Zilong-Li/vcfpp under MIT license. vcfppR is available from https://cran.r-project.org/web/packages/vcfppR.",
+  doi = "10.1093/bioinformatics/btae049"
+)

src/htslib-1.19.1/header.c

@@ -2358,7 +2358,7 @@ void sam_hdr_incr_ref(sam_hdr_t *bh) {
  * Returns a sam_hrecs_t struct on success (free with sam_hrecs_free())
  *         NULL on failure
  */
-sam_hrecs_t *sam_hrecs_new() {
+sam_hrecs_t *sam_hrecs_new(void) {
     sam_hrecs_t *hrecs = calloc(1, sizeof(*hrecs));
 
     if (!hrecs)

src/htslib-1.19.1/hts.c

@@ -81,7 +81,7 @@ KHASH_INIT2(s2i,, kh_cstr_t, int64_t, 1, kh_str_hash_func, kh_str_hash_equal)
 HTSLIB_EXPORT
 int hts_verbose = HTS_LOG_WARNING;
 
-const char *hts_version()
+const char *hts_version(void)
 {
     return HTS_VERSION_TEXT;
 }
@@ -4955,7 +4955,7 @@ int hts_resize_array_(size_t item_size, size_t num, size_t size_sz,
     return 0;
 }
 
-void hts_lib_shutdown()
+void hts_lib_shutdown(void)
 {
     hfile_shutdown(1);
 }
@@ -4969,7 +4969,7 @@ void hts_set_log_level(enum htsLogLevel level)
     hts_verbose = level;
 }
 
-enum htsLogLevel hts_get_log_level()
+enum htsLogLevel hts_get_log_level(void)
 {
     return hts_verbose;
 }

src/htslib-1.19.1/sam.c

@@ -104,7 +104,7 @@ const int8_t bam_cigar_table[256] = {
     -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1
 };
 
-sam_hdr_t *sam_hdr_init()
+sam_hdr_t *sam_hdr_init(void)
 {
     sam_hdr_t *bh = (sam_hdr_t*)calloc(1, sizeof(sam_hdr_t));
     if (bh == NULL) return NULL;
@@ -421,7 +421,7 @@ const char *sam_parse_region(sam_hdr_t *h, const char *s, int *tid,
  *** BAM alignment I/O ***
  *************************/
 
-bam1_t *bam_init1()
+bam1_t *bam_init1(void)
 {
     return (bam1_t*)calloc(1, sizeof(bam1_t));
 }

src/htslib-1.19.1/textutils.c

@@ -220,7 +220,7 @@ static char token_type(hts_json_token *token)
 }
 
 HTSLIB_EXPORT
-hts_json_token * hts_json_alloc_token() {
+hts_json_token * hts_json_alloc_token(void) {
     return calloc(1, sizeof(hts_json_token));
 }
 

src/htslib-1.19.1/vcf.c

@@ -1566,7 +1566,7 @@ int bcf_hdr_write(htsFile *hfp, bcf_hdr_t *h)
  *** BCF site I/O ***
  ********************/
 
-bcf1_t *bcf_init()
+bcf1_t *bcf_init(void)
 {
     bcf1_t *v;
     v = (bcf1_t*)calloc(1, sizeof(bcf1_t));