x86-64: Prefer 32S relocations

This target has _32 and _32S relocs (the latter being for signed
32 bit entities).  All instruction displacements have to use
the 32S variants.  Normal references like
  .long s
normally would use the _32 variant.  For normal executables this
doesn't matter.  For shared libraries neither (which use PC-relative
relocs).  But it matters for things like the kernel that are linked
to high addresses (signed ones).  There the GNU linker would error
out on overflow for the _32 variant.

To keep life simple we simply switch from _32 to _32S altogether.
Strictly speaking it's still wrong, but in practice using _32 is
more often wrong than using _32S ;)

x86_64-link.c

@@ -3,7 +3,7 @@
 #define EM_TCC_TARGET EM_X86_64
 
 /* relocation type for 32 bit data relocation */
-#define R_DATA_32   R_X86_64_32
+#define R_DATA_32   R_X86_64_32S
 #define R_DATA_PTR  R_X86_64_64
 #define R_JMP_SLOT  R_X86_64_JUMP_SLOT
 #define R_GLOB_DAT  R_X86_64_GLOB_DAT