tests: Added numerous tests.

The tests are taken almost verbatim from the open source project PicoC. It can
be found at https://code.google.com/p/picoc/.

The tests range from very simple/trivial ones to more complicated. My view is
that the more tests the better. Without tests like this I was very reluctant to
make any changes to tcc for the fear of breaking things.

The tests pass on Win32, OSX, Linux x86 and x86_64. One or two tests fail on
each platform due to differences in the runtime library.

tests2/21_char_array.c

@@ -0,0 +1,33 @@
+#include <stdio.h>
+
+int main()
+{
+   int x = 'a';
+   char y = x;
+
+   char *a = "hello";
+
+   printf("%s\n", a);
+
+   int c;
+   c = *a;
+
+   char *b;
+   for (b = a; *b != 0; b++)
+      printf("%c: %d\n", *b, *b);
+
+   char destarray[10];
+   char *dest = &destarray[0];
+   char *src = a;
+
+   while (*src != 0)
+      *dest++ = *src++;
+
+   *dest = 0;
+
+   printf("copied string is %s\n", destarray);
+
+   return 0;
+}
+
+/* vim: set expandtab ts=4 sw=3 sts=3 tw=80 :*/