Fix windows build.

R=brainman, rsc
CC=golang-dev
https://golang.org/cl/3533041

src/cmd/ld/data.c

@@ -166,7 +166,8 @@ relocsym(Sym *s)
 			continue;
 
 		if(r->sym != S && (r->sym->type == SDYNIMPORT || r->sym->dynimpname != nil))
-			diag("unhandled relocation for %s (rtype %d)", r->sym->name, r->type);
+			if (thechar != '8' || HEADTYPE != 10) // Windows PE supports relocation references to dynamic import symbols
+				diag("unhandled relocation for %s (rtype %d)", r->sym->name, r->type);
 
 		if(r->sym != S && !r->sym->reachable)
 			diag("unreachable sym in relocation: %s %s", s->name, r->sym->name);

src/pkg/Makefile

@@ -147,6 +147,10 @@ DIRS+=\
 
 endif
 
+ifeq ($(GOOS),windows)
+DIRS:=$(filter-out runtime/cgo,$(DIRS))
+endif
+
 NOTEST=\
 	debug/proc\
 	exp/draw/x11\

src/pkg/runtime/windows/mem.c

@@ -27,8 +27,8 @@ abort(int8 *name)
 
 #pragma dynimport runtime·VirtualAlloc VirtualAlloc "kernel32.dll"
 #pragma dynimport runtime·VirtualFree VirtualFree "kernel32.dll"
-void *runtime·VirtualAlloc;
-void *runtime·VirtualFree;
+extern void *runtime·VirtualAlloc;
+extern void *runtime·VirtualFree;
 
 void*
 runtime·SysAlloc(uintptr n)

src/pkg/runtime/windows/thread.c

@@ -16,25 +16,25 @@
 #pragma dynimport runtime·SetLastError SetLastError "kernel32.dll"
 
 // Also referenced by external packages
-void *runtime·CloseHandle;
-void *runtime·ExitProcess;
-void *runtime·GetStdHandle;
-void *runtime·SetEvent;
-void *runtime·WriteFile;
-void *runtime·LoadLibraryEx;
-void *runtime·GetProcAddress;
-void *runtime·GetLastError;
-void *runtime·SetLastError;
+extern void *runtime·CloseHandle;
+extern void *runtime·ExitProcess;
+extern void *runtime·GetStdHandle;
+extern void *runtime·SetEvent;
+extern void *runtime·WriteFile;
+extern void *runtime·LoadLibraryEx;
+extern void *runtime·GetProcAddress;
+extern void *runtime·GetLastError;
+extern void *runtime·SetLastError;
 
 #pragma dynimport runtime·CreateEvent CreateEventA "kernel32.dll"
 #pragma dynimport runtime·CreateThread CreateThread "kernel32.dll"
 #pragma dynimport runtime·GetModuleHandle GetModuleHandleA "kernel32.dll"
 #pragma dynimport runtime·WaitForSingleObject WaitForSingleObject "kernel32.dll"
 
-void *runtime·CreateEvent;
-void *runtime·CreateThread;
-void *runtime·GetModuleHandle;
-void *runtime·WaitForSingleObject;
+extern void *runtime·CreateEvent;
+extern void *runtime·CreateThread;
+extern void *runtime·GetModuleHandle;
+extern void *runtime·WaitForSingleObject;
 
 void
 runtime·osinit(void)
@@ -47,11 +47,11 @@ runtime·osinit(void)
 #pragma dynimport runtime·FreeEnvironmentStrings FreeEnvironmentStringsW  "kernel32.dll"
 #pragma dynimport runtime·LocalFree LocalFree "kernel32.dll"
 
-void *runtime·GetCommandLine;
-void *runtime·CommandLineToArgv;
-void *runtime·GetEnvironmentStrings;
-void *runtime·FreeEnvironmentStrings;
-void *runtime·LocalFree;
+extern void *runtime·GetCommandLine;
+extern void *runtime·CommandLineToArgv;
+extern void *runtime·GetEnvironmentStrings;
+extern void *runtime·FreeEnvironmentStrings;
+extern void *runtime·LocalFree;
 
 void
 runtime·windows_goargs(void)