Fix -DNEDUG builds

- assert() is macro which is defined as empty, while panic is always
   present. I added an explicit abort() after the macro to make sure the
   function never returns in case of wrong flags.

 - Fixed gcc build with -NDEBUG, -Os for ARM.
   * A few 'may be used uninitialized' messages
   * A few new missing support library functions where added in libminc.

Change-Id: I69fcda2cd3888390b7ddeff4c0cd849105ce86ff

usr.bin/vis/vis.c

@@ -166,6 +166,11 @@ process(FILE *fp)
 	char buff[4 * MB_LEN_MAX + 1]; /* max encoding length for one char */
 	int mbilen, cerr = 0, raerr = 0;
 	
+#if defined(__minix)
+	/* triggers a 'may be used uninitialized', when compiled with gcc,
+	 * asserts off, and -Os. */
+	rachar = 0;
+#endif /* defined(__minix) */
         /*
          * The input stream is considered to be multibyte characters.
          * The input loop will read this data inputing one character,