debug messages: implement dynamic debug

Heavily inspired off linux kernel's dynamic debug:
 * add a /sys/kernel/debug/dynamic_debug/control file
 (accessible from linux side in /sys/class/mcos/mcos0/sys/kernel/debug/dynamic_debug/control)
 * read from file to list debug statements (currently limited to 4k in size)
 * write to file with '[file foo ][func bar ][line [x][-[y]]] [+-]p' to change values

Side effects:
 * reindented all linker scripts, there is a new __verbose section
 * added string function strpbrk

Change-Id: I36d7707274dcc3ecaf200075a31a2f0f76021059

lib/include/string.h

@@ -23,6 +23,7 @@ char *strncpy(char *dest, const char *src, size_t maxlen);
 int strcmp(const char *s1, const char *s2);
 int strncmp(const char *s1, const char *s2, size_t n);
 char *strstr(const char *haystack, const char *needle);
+char *strpbrk(const char *haystack, const char *accept);
 char *strchr(const char *s, int n);
 char *strrchr(const char *s, int n);
 void *memcpy(void *dest, const void *src, size_t n);

lib/string.c

@@ -112,6 +112,19 @@ strrchr(const char *s, int c)
 	return (char *)last;
 } /* strrchr() */
 
+char *strpbrk(const char *s, const char *accept)
+{
+	const char *a;
+
+	do {
+		for (a = accept; *a; a++)
+			if (*s == *a)
+				return (char *)s;
+	} while (*(s++));
+
+	return NULL;
+}
+
 char *strstr(const char *haystack, const char *needle)
 {
 	int len = strlen(needle);