diff --git a/include/stdlib.h b/include/stdlib.h
index 75eded7d..e529f086 100644
--- a/include/stdlib.h
+++ b/include/stdlib.h
@@ -39,7 +39,7 @@ void * calloc (size_t nmemb, size_t size);
 void exit (int);
 void free (void *ptr);
 char* getenv (char const* s);
-int settenv (char const* s, char const* v, int overwrite_p);
+int setenv (char const* s, char const* v, int overwrite_p);
 void *malloc (size_t);
 void qsort (void *base, size_t nmemb, size_t size, int (*compar)(void const *, void const *));
 void *realloc (void *p, size_t size);
diff --git a/lib/libc.c b/lib/libc.c
index 2819468c..1427ba2d 100644
--- a/lib/libc.c
+++ b/lib/libc.c
@@ -279,7 +279,7 @@ malloc (size_t size)
 {
   if (!g_brk)
     g_brk = brk (0);
-  if (brk (g_brk + size) == -1)
+  if (brk (g_brk + size) == (void*)-1)
     return 0;
   char *p = g_brk;
   g_brk += size;
@@ -290,7 +290,7 @@ void *
 memcpy (void *dest, void const *src, size_t n)
 {
   char* p = dest;
-  char* q = src;
+  char const* q = src;
   while (n--) *p++ = *q++;
   return dest;
 }
diff --git a/src/gc.c b/src/gc.c
index 71751252..6f34aeba 100644
--- a/src/gc.c
+++ b/src/gc.c
@@ -177,9 +177,9 @@ gc_ () ///((internal))
       if (g_debug > 2)
         {
           eputs (" up[");
-          eputs (itoa (g_cells));
+          eputs (itoa ((unsigned long)g_cells));
           eputs (",");
-          eputs (itoa (g_news));
+          eputs (itoa ((unsigned long)g_news));
           eputs (":");
           eputs (itoa (ARENA_SIZE));
           eputs (",");
diff --git a/src/posix.c b/src/posix.c
index e8ec52a1..5986020b 100644
--- a/src/posix.c
+++ b/src/posix.c
@@ -18,7 +18,9 @@
  * along with Mes.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <sys/stat.h>
 #include <fcntl.h>
+#include <stdlib.h>
 #include <unistd.h>
 
 int
@@ -203,7 +205,7 @@ force_output (SCM p) ///((arity . n))
 SCM
 chmod_ (SCM file_name, SCM mode) ///((name . "chmod"))
 {
-  return chmod (string_to_cstring (file_name), VALUE (mode));
+  chmod (string_to_cstring (file_name), VALUE (mode));
   return cell_unspecified;
 }