Index: uspace/lib/c/include/malloc.h
===================================================================
--- uspace/lib/c/include/malloc.h	(revision 4805495a910f793f8918c13f029a38a5bb548154)
+++ uspace/lib/c/include/malloc.h	(revision c8cf261a450bf22fa6cc6e9872a1f07f9e7dccda)
@@ -37,4 +37,7 @@
 
 #include <stddef.h>
+#include <_bits/decls.h>
+
+__C_DECLS_BEGIN;
 
 extern void *malloc(size_t size)
@@ -42,10 +45,19 @@
 extern void *calloc(size_t nmemb, size_t size)
     __attribute__((malloc));
-extern void *memalign(size_t align, size_t size)
-    __attribute__((malloc));
 extern void *realloc(void *addr, size_t size)
     __attribute__((warn_unused_result));
 extern void free(void *addr);
+
+__C_DECLS_END;
+
+#ifdef _HELENOS_SOURCE
+__HELENOS_DECLS_BEGIN;
+
+extern void *memalign(size_t align, size_t size)
+    __attribute__((malloc));
 extern void *heap_check(void);
+
+__HELENOS_DECLS_END;
+#endif
 
 #endif