diff --git a/extlib/benz/error.c b/extlib/benz/error.c
index d9ea00dd..8882da54 100644
--- a/extlib/benz/error.c
+++ b/extlib/benz/error.c
@@ -7,14 +7,14 @@
 void
 pic_panic(pic_state PIC_UNUSED(*pic), const char *msg)
 {
+  extern void abort();
+
 #if DEBUG
   fprintf(stderr, "abort: %s\n", msg);
 #else
   (void)msg;
 #endif
   PIC_ABORT(pic);
-
-  PIC_UNREACHABLE();
 }
 
 void
diff --git a/extlib/benz/include/picrin/value.h b/extlib/benz/include/picrin/value.h
index 42c65295..c821d06f 100644
--- a/extlib/benz/include/picrin/value.h
+++ b/extlib/benz/include/picrin/value.h
@@ -220,9 +220,8 @@ pic_valid_int(double v)
 
 #else
 PIC_INLINE bool
-pic_valid_int(int v)
+pic_valid_int(int PIC_UNUSED(v))
 {
-  PIC_UNUSED(v);
   return true;
 }
 #endif
diff --git a/extlib/benz/vm.c b/extlib/benz/vm.c
index c6cb42b1..0daf0c72 100644
--- a/extlib/benz/vm.c
+++ b/extlib/benz/vm.c
@@ -109,9 +109,9 @@ pic_get_args(pic_state *pic, const char *format, ...)
 #if PIC_ENABLE_FLOAT
     case 'f': {
       double *f;
+      pic_value v;
 
       f = va_arg(ap, double *);
-      pic_value v;
 
       v = GET_OPERAND(pic, i);
       switch (pic_type(v)) {
@@ -129,10 +129,10 @@ pic_get_args(pic_state *pic, const char *format, ...)
     case 'F': {
       double *f;
       bool *e;
+      pic_value v;
 
       f = va_arg(ap, double *);
       e = va_arg(ap, bool *);
-      pic_value v;
 
       v = GET_OPERAND(pic, i);
       switch (pic_type(v)) {
@@ -152,10 +152,10 @@ pic_get_args(pic_state *pic, const char *format, ...)
     case 'I': {
       int *k;
       bool *e;
+      pic_value v;
 
       k = va_arg(ap, int *);
       e = va_arg(ap, bool *);
-      pic_value v;
 
       v = GET_OPERAND(pic, i);
       switch (pic_type(v)) {
@@ -175,9 +175,9 @@ pic_get_args(pic_state *pic, const char *format, ...)
 #endif
     case 'i': {
       int *k;
+      pic_value v;
 
       k = va_arg(ap, int *);
-      pic_value v;
 
       v = GET_OPERAND(pic, i);
       switch (pic_type(v)) {
@@ -196,12 +196,12 @@ pic_get_args(pic_state *pic, const char *format, ...)
     }
     case 'k': {
       size_t *k;
-
-      k = va_arg(ap, size_t *);
       pic_value v;
       int x;
       size_t s;
 
+      k = va_arg(ap, size_t *);
+
       v = GET_OPERAND(pic, i);
       switch (pic_type(v)) {
       case PIC_TT_INT:
diff --git a/extlib/benz/xfile.c b/extlib/benz/xfile.c
index d09bf9bf..a071aced 100644
--- a/extlib/benz/xfile.c
+++ b/extlib/benz/xfile.c
@@ -94,6 +94,8 @@ xFILE *xfunopen(void *cookie, int (*read)(void *, char *, int), int (*write)(voi
 }
 
 int xfclose(xFILE *fp) {
+  extern void free(void *);     /* FIXME */
+
   xfflush(fp);
   fp->flag = 0;
   if (fp->base != fp->buf)
@@ -102,6 +104,7 @@ int xfclose(xFILE *fp) {
 }
 
 int x_fillbuf(xFILE *fp) {
+  extern void *malloc(size_t);  /* FIXME */
   int bufsize;
 
   if ((fp->flag & (X_READ|X_EOF|X_ERR)) != X_READ)
@@ -136,6 +139,7 @@ int x_fillbuf(xFILE *fp) {
 }
 
 int x_flushbuf(int x, xFILE *fp) {
+  extern void *malloc(size_t);  /* FIXME */
   int num_written=0, bufsize=0;
   char c = x;
 
@@ -284,14 +288,15 @@ int xungetc(int c, xFILE *fp) {
 }
 
 size_t xfread(void *ptr, size_t size, size_t count, xFILE *fp) {
+  char *bptr = ptr;
   long nbytes;
   int c;
 
   nbytes = size * count;
   while (nbytes > fp->cnt) {
-    memcpy((char *)ptr, fp->ptr, fp->cnt);
+    memcpy(bptr, fp->ptr, fp->cnt);
     fp->ptr += fp->cnt;
-    ptr += fp->cnt;
+    bptr += fp->cnt;
     nbytes -= fp->cnt;
     if ((c = x_fillbuf(fp)) == EOF) {
       return (size * count - nbytes) / size;
@@ -299,26 +304,27 @@ size_t xfread(void *ptr, size_t size, size_t count, xFILE *fp) {
       xungetc(c, fp);
     }
   }
-  memcpy((char *)ptr, fp->ptr, nbytes);
+  memcpy(bptr, fp->ptr, nbytes);
   fp->ptr += nbytes;
   fp->cnt -= nbytes;
   return count;
 }
 
 size_t xfwrite(const void *ptr, size_t size, size_t count, xFILE *fp) {
+  const char *bptr = ptr;
   long nbytes;
 
   nbytes = size * count;
   while (nbytes > fp->cnt) {
-    memcpy(fp->ptr, (char *)ptr, fp->cnt);
+    memcpy(fp->ptr, bptr, fp->cnt);
     fp->ptr += fp->cnt;
-    ptr += fp->cnt;
+    bptr += fp->cnt;
     nbytes -= fp->cnt;
     if (x_flushbuf(EOF, fp) == EOF) {
       return (size * count - nbytes) / size;
     }
   }
-  memcpy(fp->ptr, (char *)ptr, nbytes);
+  memcpy(fp->ptr, bptr, nbytes);
   fp->ptr += nbytes;
   fp->cnt -= nbytes;
   return count;