* dcrt0.cc (dll_crt0_0): Remove call to wincap.init.

* init.cc (dll_entry): Rename is_wow64_proc to wow64_test_stack_marker.
	Call wincap.init here before doing anything else.  Use wincap.is_wow64
	to determine if we're running in a WOW64 emulator.
	* mmap.cc (MapViewNT): Don't use AT_ROUND_TO_PAGE in WOW64, it's
	apparently not supported.
	(mmap64): Don't create mappings beyond EOF, which would need to use
	AT_ROUND_TO_PAGE, on WOW64.
	* wincap.cc (wincap): Throw into the .cygwin_dll_common section.
	(wincapc::init): Determine if running in WOW64 and set wow_64 flag.
	* wincap.h (class wincapc): Add wow64 member.
	(wincapc::is_wow64): New method.

winsup/cygwin/wincap.h

@@ -70,6 +70,7 @@ class wincapc
 {
   OSVERSIONINFOEX  version;
   char             osnam[40];
+  bool             wow64;
   void             *caps;
 
 public:
@@ -78,6 +79,7 @@ public:
   void set_chunksize (DWORD nchunksize);
 
   const char *osname () const { return osnam; }
+  const bool is_wow64 () const { return wow64; }
 
 #define IMPLEMENT(cap) cap() const { return ((wincaps *) this->caps)->cap; }