Add string accessors, working towards first program

ccodegen.cpp

@@ -405,7 +405,30 @@ compile_string(String filecontent, String filename = "default_name"_s){
 
 
   gen(R"==(
-    // Generated 
+
+#include <stdint.h>
+typedef int8_t   S8;
+typedef int16_t  S16;
+typedef int32_t  S32;
+typedef int64_t  S64;
+typedef uint8_t  U8;
+typedef uint16_t U16;
+typedef uint32_t U32;
+typedef uint64_t U64;
+typedef S8       B8;
+typedef S16      B16;
+typedef S32      B32;
+typedef S64      B64;
+typedef U64      SizeU;
+typedef S64      SizeI;
+typedef float    F32;
+typedef double   F64;
+
+struct String{
+  U8 *str;
+  S64 len;
+};
+
   )==");
 
   F64 resolve_begin = os_time();