Fix warnings on Windows and reimplement err and errx as functions

jo.c

@@ -47,11 +47,35 @@
 static JsonNode *pile;		/* pile of nested objects/arrays */
 
 #if defined(_WIN32) || defined(_AIX)
-# define err(n, s)	{ fprintf(stderr, s); exit(n); }
-# define errx(n, f, a)	{ fprintf(stderr, f, a); exit(n); }
+#include <errno.h>
+#include <stdarg.h>
+static inline void err(int eval, const char *fmt, ...) {
+	int errnum = errno;
+
+	va_list ap;
+	va_start(ap, fmt);
+
+	fprintf(stderr, "jo: ");
+	vfprintf(stderr, fmt, ap);
+	fprintf(stderr, ": %s\n", strerror(errnum));
+
+	va_end(ap);
+	exit(eval);
+}
+static inline void errx(int eval, const char *fmt, ...) {
+	va_list ap;
+	va_start(ap, fmt);
+
+	fprintf(stderr, "jo: ");
+	vfprintf(stderr, fmt, ap);
+	fprintf(stderr, "\n");
+
+	va_end(ap);
+	exit(eval);
+}
 #endif
 
-#ifdef _WIN32
+#if defined(_WIN32) && !defined(fseeko)
 # define fseeko	fseek
 # define ftello	ftell
 #endif
@@ -167,7 +191,7 @@ char *slurp_file(const char* filename, size_t *out_len, bool fold_newlines)
 	}
 
 	buf = slurp(fp, buffer_len, EOF, out_len, fold_newlines);
-	if (*out_len < 0) {
+	if (*out_len == (size_t)-1) {
 		errx(1, "File %s is too large to be read into memory", filename);
 	}
 	if (!use_stdin) fclose(fp);
@@ -179,7 +203,7 @@ char *slurp_line(FILE *fp, size_t *out_len)
 	char *buf;
 
 	buf = slurp(fp, SLURP_BLOCK_SIZE, '\n', out_len, false);
-	if (*out_len < 0) {
+	if (*out_len == (size_t)-1) {
 		errx(1, "Line too large to be read into memory");
 	}
 	return buf;
@@ -545,7 +569,7 @@ char* utf8_from_locale(const char *str, size_t len)
 	if (len == 0) {
 		return strdup("");
 	}
-	if (len == -1) {
+	if (len == (size_t)-1) {
 		len = strlen(str);
 	}
 	wcssize = MultiByteToWideChar(GetACP(), 0, str, len,  NULL, 0);
@@ -578,7 +602,7 @@ char* locale_from_utf8(const char *utf8, size_t len)
 	if (len == 0) {
 		return strdup("");
 	}
-	if (len == -1) {
+	if (len == (size_t)-1) {
 		len = strlen(utf8);
 	}
 	wcssize = MultiByteToWideChar(CP_UTF8, 0, utf8, len,  NULL, 0);