when open macro GENERATED_CODE_COVERAGE, fix compiler error and fd leak

src/mips64/simulator-mips64.cc

Index: src/mips64/simulator-mips64.cc
diff --git a/src/mips64/simulator-mips64.cc b/src/mips64/simulator-mips64.cc
index 86e8b91464eacbd74a54294a7a14fee232673782..bcc502f001ef0e544fd531c3eea201ecd2f6783c 100644
--- a/src/mips64/simulator-mips64.cc
+++ b/src/mips64/simulator-mips64.cc
@@ -111,11 +111,17 @@ static FILE* coverage_log = NULL;
 
 static void InitializeCoverage() {
   char* file_name = getenv("V8_GENERATED_CODE_COVERAGE_LOG");
-  if (file_name != NULL) {
+  if (file_name != NULL && NULL == coverage_log) {
     coverage_log = fopen(file_name, "aw+");
   }
 }
 
+static void DeinitCoverageLog() {
+	if (coverage_log != NULL) {
+		fclose(coverage_log);
+		coverage_log = NULL;
+	}
+}
 
 void MipsDebugger::Stop(Instruction* instr) {
   // Get the stop code.
@@ -150,6 +156,7 @@ void MipsDebugger::Stop(Instruction* instr) {
 #define UNSUPPORTED() printf("Unsupported instruction.\n");
 
 static void InitializeCoverage() {}
+static void DeinitCoverageLog() {}
 
 
 void MipsDebugger::Stop(Instruction* instr) {