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.

tests2/51_static.c

@@ -0,0 +1,30 @@
+#include <stdio.h>
+
+static int fred = 1234;
+static int joe;
+
+void henry()
+{
+   static int fred = 4567;
+
+   printf("%d\n", fred);
+   fred++;
+}
+
+int main()
+{
+   printf("%d\n", fred);
+   henry();
+   henry();
+   henry();
+   henry();
+   printf("%d\n", fred);
+   fred = 8901;
+   joe = 2345;
+   printf("%d\n", fred);
+   printf("%d\n", joe);
+
+   return 0;
+}
+
+/* vim: set expandtab ts=4 sw=3 sts=3 tw=80 :*/