refactor(libc): clean up dependencies in libc

- Removing platform dependencies from libc modules.
- Replacing panicking with actual error handling.
- Debug macros are included indirectly from assert.h. Removing
  "platform_def.h" from assert.h and adding "common/debug.h"
  where the macros are used.
- Removing hack for fixing PLAT_LOG_LEVEL_ASSERT to 40.
  Instead removing assert with expression, as this
  does not provide additional information.

Signed-off-by: Claus Pedersen <claustbp@google.com>
Change-Id: Icc201ea7b63c1277e423c1cfd13fd6816c2bc568

lib/libc/snprintf.c

@@ -6,11 +6,10 @@
 
 #include <assert.h>
 #include <stdarg.h>
+#include <stdbool.h>
+#include <stddef.h>
 #include <stdint.h>
 
-#include <common/debug.h>
-#include <plat/common/platform.h>
-
 #define get_num_va_args(_args, _lcount)				\
 	(((_lcount) > 1)  ? va_arg(_args, long long int) :	\
 	(((_lcount) == 1) ? va_arg(_args, long int) :		\
@@ -51,10 +50,10 @@ static void unsigned_num_print(char **s, size_t n, size_t *chars_printed,
 	unsigned int rem;
 	char ascii_a = capitalise ? 'A' : 'a';
 
+	/* num_buf is only large enough for radix >= 10 */
 	if (radix < 10) {
-		ERROR("snprintf: unsupported radix '%u'.", radix);
-		plat_panic_handler();
-		assert(0); /* Unreachable */
+		assert(0);
+		return;
 	}
 
 	do {
@@ -218,11 +217,8 @@ loop:
 				break;
 
 			default:
-				/* Panic on any other format specifier. */
-				ERROR("snprintf: specifier with ASCII code '%d' not supported.",
-				      *fmt);
-				plat_panic_handler();
-				assert(0); /* Unreachable */
+				CHECK_AND_PUT_CHAR(s, n, chars_printed, '%');
+				CHECK_AND_PUT_CHAR(s, n, chars_printed, *fmt);
 			}
 			fmt++;
 			continue;