Supports building gtest as a DLL (by Vlad Losev).

include/gtest/gtest-death-test.h

@@ -176,7 +176,7 @@ GTEST_DECLARE_string_(death_test_style);
 // Two predicate classes that can be used in {ASSERT,EXPECT}_EXIT*:
 
 // Tests that an exit code describes a normal exit with a given exit code.
-class ExitedWithCode {
+class GTEST_API_ ExitedWithCode {
  public:
   explicit ExitedWithCode(int exit_code);
   bool operator()(int exit_status) const;
@@ -190,7 +190,7 @@ class ExitedWithCode {
 #if !GTEST_OS_WINDOWS
 // Tests that an exit code describes an exit due to termination by a
 // given signal.
-class KilledBySignal {
+class GTEST_API_ KilledBySignal {
  public:
   explicit KilledBySignal(int signum);
   bool operator()(int exit_status) const;