refactor: Add original .c package files by Jef.

After my changes to the macros, they still feel a bit hacky, but I'm content with them. I also changed the parser to assume the .PKGINFO files are always valid because they are automatically generated. The parser also assumes the same fields will always appear in the same fixed order. I made this change after checking how makepkg generated this file.

@@ -0,0 +20,4 @@
+/*
+ * Deallocate a package.
+ */
+void vieter_package_free(Pkg ** ptp);

@@ -0,0 +1,158 @@
+/*********************************************************************

@@ -0,0 +4,4 @@
+#define SMALL_BUFF_SIZE 128
+
+#define ADD_STRING(section, field) if (info->field != 0) { \
+	snprintf(aux, SMALL_BUFF_SIZE, section, info->field); \

@@ -0,0 +18,4 @@
+		buff_size *= 2; \
+	} \
+	strcat(description, aux); \
+	while (info->field->array[i] != NULL) { \

@@ -0,0 +38,4 @@
+static size_t ignored_words_len = sizeof(ignored_names) / sizeof(char *);
+
+Pkg *vieter_package_init() {
+	return calloc(sizeof(pkg_info), 1);

@@ -0,0 +58,4 @@
+
+	// Exit early if we weren't able to successfully open the archive for reading
+	if (r != ARCHIVE_OK) {
+		return NULL;

@@ -0,0 +103,4 @@
+	// Get size of file
+	struct stat stats;
+
+	if (stat(pkg_path, &stats) != 0) {

@@ -0,0 +121,4 @@
+	return pkg;
+}
+
+void vieter_package_sha256sum(Pkg *pkg, char *res) {

@@ -0,0 +152,4 @@
+		// We transform the first half byte into the second character to keep
+		// each byte from becoming reversed in the final string
+		half_byte = hash[i] & 0b1111;
+		if (half_byte < 10) {

@@ -0,0 +173,4 @@
+char *vieter_package_to_description(Pkg *pkg) {
+	pkg_info *info = pkg->info;
+
+	size_t buff_size = 1024;

@@ -0,0 +181,4 @@
+
+	// special case for FILENAME
+	// assuming .pkg.tar.zst; other formats are valid, this should account for that
+	snprintf(aux, SMALL_BUFF_SIZE, "%%FILENAME%%\n%s-%s-%s.pkg.tar.zst", info->name, info->version,

@@ -0,0 +3,4 @@
+#include "vieter_package_info.h"
+
+#define PKG_INFO_STRING(key_ptr, field) if ((value_ptr = strstr(value_ptr, key_ptr)) != NULL) { \
+	value_ptr += strlen(key_ptr);\