Index: uspace/lib/c/Makefile
===================================================================
--- uspace/lib/c/Makefile	(revision 7a6065c264dbab78e1758685fd1eda498ab9b73d)
+++ uspace/lib/c/Makefile	(revision c9e09f26171e31413438891ef35603df24ce8ac7)
@@ -44,4 +44,6 @@
 LIBRARY = libc
 SOVERSION = 0.0
+
+EXTRA_CFLAGS = -fno-builtin
 
 -include $(CONFIG_MAKEFILE)