Fix Windows/MinGW build: reserved errno parameter name, missing err.h

src/mfoc.c

@@ -753,7 +753,7 @@ int main(int argc, char *const argv[])
   exit(EXIT_FAILURE);
 }
 
-void usage(FILE *stream, int errno)
+void usage(FILE *stream, int exit_code)
 {
   fprintf(stream, "Usage: mfoc [-h] [-k key] [-f file] ... [-P probnum] [-T tolerance] [-O output]\n");
   fprintf(stream, "\n");
@@ -776,7 +776,7 @@ void usage(FILE *stream, int errno)
   fprintf(stream, "\n");
   fprintf(stream, "This is mfoc version %s.\n", PACKAGE_VERSION);
   fprintf(stream, "For more information, run: 'man mfoc'.\n");
-  exit(errno);
+  exit(exit_code);
 }
 
 void mf_init(mfreader *r)

src/mfoc.h

@@ -82,7 +82,7 @@ typedef struct {
 } countKeys;
 
 
-void usage(FILE *stream, int errno);
+void usage(FILE *stream, int exit_code);
 void mf_init(mfreader *r);
 void mf_configure(nfc_device *pdi);
 void mf_select_tag(nfc_device *pdi, nfc_target *pnt);

src/nfc-utils.c

@@ -37,7 +37,6 @@
  * @brief Provide some examples shared functions like print, parity calculation, options parsing.
  */
 #include <nfc/nfc.h>
-#include <err.h>
 
 #include "nfc-utils.h"
 

src/nfc-utils.h

@@ -43,7 +43,20 @@
 
 #  include <stdlib.h>
 #  include <string.h>
-#  include <err.h>
+#  ifdef _WIN32
+#    include <stdio.h>
+#    include <stdarg.h>
+static inline void warnx(const char *fmt, ...)
+{
+  va_list ap;
+  va_start(ap, fmt);
+  vfprintf(stderr, fmt, ap);
+  va_end(ap);
+  fprintf(stderr, "\n");
+}
+#  else
+#    include <err.h>
+#  endif
 
 /**
  * @macro DBG