Kernel: Force strlen compilation so BAN can use it

kernel/Makefile

@@ -31,6 +31,7 @@ BUILDDIR=$(abspath build)
  
 KERNEL_OBJS=			\
 $(KERNEL_ARCH_OBJS)		\
+kernel/build_libc.o		\
 kernel/kernel.o			\
 kernel/Keyboard.o		\
 kernel/kmalloc.o		\

kernel/kernel/build_libc.cpp

@@ -0,0 +1,6 @@
+#include <string.h>
+
+void foo()
+{
+	strlen("");
+}