Bug 790589 - Add env variable to define the cc/gc log directory, r=mccr8

xpcom/base/nsCycleCollector.cpp

@@ -1303,17 +1303,22 @@ public:
         }
         char basename[MAXPATHLEN] = {'\0'};
         char ccname[MAXPATHLEN] = {'\0'};
+        char* env;
+        if ((env = PR_GetEnv("MOZ_CC_LOG_DIRECTORY"))) {
+            strcpy(basename, env);
+        } else {
 #ifdef XP_WIN
-        // On Windows, tmpnam returns useless stuff, such as "\\s164.".
-        // Therefore we need to call the APIs directly.
-        GetTempPathA(mozilla::ArrayLength(basename), basename);
+            // On Windows, tmpnam returns useless stuff, such as "\\s164.".
+            // Therefore we need to call the APIs directly.
+            GetTempPathA(mozilla::ArrayLength(basename), basename);
 #else
-        tmpnam(basename);
-        char *lastSlash = strrchr(basename, XPCOM_FILE_PATH_SEPARATOR[0]);
-        if (lastSlash) {
-            *lastSlash = '\0';
-        }
+            tmpnam(basename);
+            char *lastSlash = strrchr(basename, XPCOM_FILE_PATH_SEPARATOR[0]);
+            if (lastSlash) {
+                *lastSlash = '\0';
+            }
 #endif
+        }
 
         ++gLogCounter;