fixes & cleanups

- tccgen.c/tcc.h: allow function declaration after use:
      int f() { return g(); }
      int g() { return 1; }
  may be a warning but not an error
  see also 76cb1144ef

- tccgen.c: redundant code related to inline functions removed
  (functions used anywhere have sym->c set automatically)

- tccgen.c: make 32bit llop non-equal test portable
  (probably not on C67)

- dynarray_add: change prototype to possibly avoid aliasing
  problems or at least warnings

- lib/alloca*.S: ".section .note.GNU-stack,"",%progbits" removed
  (has no effect)

- tccpe: set SizeOfCode field (for correct upx decompression)

- libtcc.c: fixed alternative -run invocation
      tcc "-run -lxxx ..." file.c
  (meant to load the library after file).
  Also supported now:
      tcc files ... options ... -run @ arguments ...

x86_64-gen.c

@@ -224,7 +224,7 @@ static int is64_type(int t)
 }
 
 /* instruction + 4 bytes data. Return the address of the data */
-ST_FUNC int oad(int c, int s)
+static int oad(int c, int s)
 {
     int t;
     if (nocode_wanted)