Remove signal-source headers from public API

Those headers implement a platform-specific mechanism. They are never
used by components directly.

This patch also cleans up a few other remaining platform-specific
artifact such as the Fiasco.OC-specific assert.h.

Issue #1993

repos/base-foc/src/include/base/internal/cap_alloc.h

@@ -16,12 +16,12 @@
 
 /* Genode includes */
 #include <base/native_capability.h>
-#include <util/assert.h>
 #include <util/construct_at.h>
 #include <foc/native_capability.h>
 
 /* base-internal includes */
 #include <base/internal/cap_map.h>
+#include <base/internal/foc_assert.h>
 
 namespace Genode {
 

repos/base-foc/src/include/base/internal/foc_assert.h

@@ -0,0 +1,32 @@
+/*
+ * \brief  Assertion macros for Fiasco.OC
+ * \author Stefan Kalkowski
+ * \date   2012-05-25
+ */
+
+/*
+ * Copyright (C) 2006-2013 Genode Labs GmbH
+ *
+ * This file is part of the Genode OS framework, which is distributed
+ * under the terms of the GNU General Public License version 2.
+ */
+
+#ifndef _INCLUDE__BASE__INTERNAL__FOC_ASSERT_H_
+#define _INCLUDE__BASE__INTERNAL__FOC_ASSERT_H_
+
+/* Genode includes */
+#include <base/log.h>
+
+/* Fiasco includes */
+namespace Fiasco {
+#include <l4/sys/kdebug.h>
+}
+
+#define ASSERT(e, s) \
+	do { if (!(e)) { \
+		Genode::raw("assertion failed: ", s, __FILE__, __LINE__); \
+		enter_kdebug("ASSERT"); \
+		} \
+	} while(0)
+
+#endif /* _INCLUDE__BASE__INTERNAL__FOC_ASSERT_H_ */