diff --git a/configure.ac b/configure.ac
index 87f27b7..8242430 100644
--- a/configure.ac
+++ b/configure.ac
@@ -284,6 +284,7 @@ AC_CHECK_DECLS([cfree,
                 valloc,
                 pvalloc],,,
                [#define _XOPEN_SOURCE 600
+                #define _QNX_SOURCE 1
                 #include <stdlib.h>
                 #include <malloc.h>])
 
diff --git a/src/libc_override_gcc_and_weak.h b/src/libc_override_gcc_and_weak.h
index 9c4d6a1..80ac4b7 100644
--- a/src/libc_override_gcc_and_weak.h
+++ b/src/libc_override_gcc_and_weak.h
@@ -212,7 +212,12 @@ extern "C" {
   void free(void* ptr) __THROW                    ALIAS(tc_free);
   void* realloc(void* ptr, size_t size) __THROW   ALIAS(tc_realloc);
   void* calloc(size_t n, size_t size) __THROW     ALIAS(tc_calloc);
+#if __QNXNTO__
+  // QNX has crazy cfree declaration
+  int cfree(void* ptr) { tc_cfree(ptr); return 0; }
+#else
   void cfree(void* ptr) __THROW                   ALIAS(tc_cfree);
+#endif
   void* memalign(size_t align, size_t s) __THROW  ALIAS(tc_memalign);
   void* aligned_alloc(size_t align, size_t s) __THROW ALIAS(tc_memalign);
   void* valloc(size_t size) __THROW               ALIAS(tc_valloc);
@@ -222,7 +227,11 @@ extern "C" {
 #ifndef __UCLIBC__
   void malloc_stats(void) __THROW                 ALIAS(tc_malloc_stats);
 #endif
+#if __QNXNTO__
+  int mallopt(int, intptr_t) ALIAS(tc_mallopt);
+#else
   int mallopt(int cmd, int value) __THROW         ALIAS(tc_mallopt);
+#endif
 #ifdef HAVE_STRUCT_MALLINFO
   struct mallinfo mallinfo(void) __THROW          ALIAS(tc_mallinfo);
 #endif