Based on:
  https://hg.mozilla.org/releases/mozilla-esr52/raw-rev/d303b3bb88c3

Adapted to apply cleanly to IceCat.

# HG changeset patch
# User Philip Chimento <philip.chimento@gmail.com>
# Date 1510012155 28800
# Node ID d303b3bb88c3345d3a089901e2b6fe883d148e44
# Parent  0152d097672f7e99504815cf7b06d9f303419fba
Bug 1414945 - Don't use TimeDuration in static initializer. r=jandem, a=ritu

On Darwin this would cause a race between two static initializers.

diff --git a/js/src/shell/js.cpp b/js/src/shell/js.cpp
--- a/js/src/shell/js.cpp
+++ b/js/src/shell/js.cpp
@@ -138,17 +138,17 @@ static const size_t gMaxStackSize = 2 * 
 #else
 static const size_t gMaxStackSize = 128 * sizeof(size_t) * 1024;
 #endif
 
 /*
  * Limit the timeout to 30 minutes to prevent an overflow on platfoms
  * that represent the time internally in microseconds using 32-bit int.
  */
-static const TimeDuration MAX_TIMEOUT_INTERVAL = TimeDuration::FromSeconds(1800.0);
+static const double MAX_TIMEOUT_SECONDS = 1800.0;
 
 // SharedArrayBuffer and Atomics settings track IceCat.  Choose a custom setting
 // with --shared-memory={on,off}.
 #ifndef RELEASE_OR_BETA
 # define SHARED_MEMORY_DEFAULT 1
 #else
 # define SHARED_MEMORY_DEFAULT 0
 #endif
@@ -3518,16 +3518,17 @@ Sleep_fn(JSContext* cx, unsigned argc, V
         if (!ToNumber(cx, args[0], &t_secs))
             return false;
         if (mozilla::IsNaN(t_secs)) {
             JS_ReportErrorASCII(cx, "sleep interval is not a number");
             return false;
         }
 
         duration = TimeDuration::FromSeconds(Max(0.0, t_secs));
+        const TimeDuration MAX_TIMEOUT_INTERVAL = TimeDuration::FromSeconds(MAX_TIMEOUT_SECONDS);
         if (duration > MAX_TIMEOUT_INTERVAL) {
             JS_ReportErrorASCII(cx, "Excessive sleep interval");
             return false;
         }
     }
     {
         LockGuard<Mutex> guard(sc->watchdogLock);
         TimeStamp toWakeup = TimeStamp::Now() + duration;
@@ -3675,16 +3676,17 @@ CancelExecution(JSContext* cx)
 
 static bool
 SetTimeoutValue(JSContext* cx, double t)
 {
     if (mozilla::IsNaN(t)) {
         JS_ReportErrorASCII(cx, "timeout is not a number");
         return false;
     }
+    const TimeDuration MAX_TIMEOUT_INTERVAL = TimeDuration::FromSeconds(MAX_TIMEOUT_SECONDS);
     if (TimeDuration::FromSeconds(t) > MAX_TIMEOUT_INTERVAL) {
         JS_ReportErrorASCII(cx, "Excessive timeout value");
         return false;
     }
     GetShellContext(cx)->timeoutInterval = t;
     if (!ScheduleWatchdog(cx, t)) {
         JS_ReportErrorASCII(cx, "Failed to create the watchdog");
         return false;