diff --git a/contrib/05.r7rs/src/file.c b/contrib/05.r7rs/src/file.c
index ba68780c..340a5e6d 100644
--- a/contrib/05.r7rs/src/file.c
+++ b/contrib/05.r7rs/src/file.c
@@ -4,6 +4,8 @@
 
 #include "picrin.h"
 
+#include <stdio.h>
+
 PIC_NORETURN static void
 file_error(pic_state *pic, const char *msg)
 {
diff --git a/etc/mkloader.pl b/etc/mkloader.pl
index 3f5bcb41..602a8aae 100755
--- a/etc/mkloader.pl
+++ b/etc/mkloader.pl
@@ -50,9 +50,9 @@ foreach my $file (@ARGV) {
   }
   pic_catch {
     /* error! */
-    fputs("fatal error: failure in loading $dirname/$basename\\n", stderr);
-    fputs(pic_errmsg(pic), stderr);
-    abort();
+    xfputs(pic, "fatal error: failure in loading $dirname/$basename\\n", xstderr);
+    xfputs(pic, pic_errmsg(pic), xstderr);
+    pic_panic(pic, "load error");
   }
 EOL
 }
diff --git a/extlib/benz/file.c b/extlib/benz/file.c
index 2a8b2c18..640a6edb 100644
--- a/extlib/benz/file.c
+++ b/extlib/benz/file.c
@@ -105,7 +105,7 @@ int x_flushbuf(pic_state *pic, int x, xFILE *fp) {
     }
 
     fp->ptr = fp->base;
-    fp->cnt = BUFSIZ - 1;
+    fp->cnt = XBUFSIZ - 1;
   }
 
   if (num_written == bufsize) {
diff --git a/extlib/benz/include/picrin/file.h b/extlib/benz/include/picrin/file.h
index a38c6a25..b07e1a27 100644
--- a/extlib/benz/include/picrin/file.h
+++ b/extlib/benz/include/picrin/file.h
@@ -5,8 +5,6 @@
 extern "C" {
 #endif
 
-#include <stdio.h>
-
 #ifndef EOF
 # define EOF (-1)
 #endif
diff --git a/extlib/benz/port.c b/extlib/benz/port.c
index 5fadc5d7..518b95b2 100644
--- a/extlib/benz/port.c
+++ b/extlib/benz/port.c
@@ -4,6 +4,8 @@
 
 #include "picrin.h"
 
+#include <stdio.h>
+
 pic_value
 pic_eof_object()
 {
@@ -69,7 +71,10 @@ file_seek(pic_state PIC_UNUSED(*pic), void *cookie, long pos, int whence) {
     whence = SEEK_END;
     break;
   }
-  return fseek(cookie, pos, whence);
+  if (fseek(cookie, pos, whence) == 0) {
+    return ftell(cookie);
+  }
+  return -1;
 }
 
 static int