diff --git a/config/rules.mk b/config/rules.mk
index d7cbf60987..2078a5160c 100644
--- a/config/rules.mk
+++ b/config/rules.mk
@@ -411,6 +411,10 @@ EXTRA_DSO_LDOPTS += -Wl,--version-script,$(SYMBOLS_FILE)
 else
 ifeq ($(OS_TARGET),Darwin)
 EXTRA_DSO_LDOPTS += -Wl,-exported_symbols_list,$(SYMBOLS_FILE)
+else
+ifeq ($(OS_TARGET),SunOS)
+EXTRA_DSO_LDOPTS += -Wl,-M,$(SYMBOLS_FILE)
+endif
 endif
 endif
 endif
diff --git a/dom/base/EventSource.cpp b/dom/base/EventSource.cpp
index 06cabc3098..32329098e2 100644
--- a/dom/base/EventSource.cpp
+++ b/dom/base/EventSource.cpp
@@ -190,6 +190,7 @@ public:
 
   bool IsClosed()
   {
+    MutexAutoLock lock(mMutex); 
     return ReadyState() == CLOSED;
   }
 
diff --git a/old-configure.in b/old-configure.in
index f949285e22..3093858a43 100644
--- a/old-configure.in
+++ b/old-configure.in
@@ -5579,7 +5579,14 @@ ac_configure_args="$_SUBDIR_CONFIG_ARGS"
 
 # --with-system-nspr will have been converted into the relevant $NSPR_CFLAGS
 # and $NSPR_LIBS.
-ac_configure_args="`echo $ac_configure_args | sed -e 's/--with-system-nspr\S* *//'`"
+case "${OS_TARGET}" in
+  Darwin|DragonFly|FreeBSD|NetBSD|OpenBSD)
+    ac_configure_args="`echo $ac_configure_args | sed -e 's/--with-system-nspr[^[:space:]]* *//'`"
+    ;;
+  *)
+    ac_configure_args="`echo $ac_configure_args | ${TOOLCHAIN_PREFIX}sed -e 's/--with-system-nspr\S* *//'`"
+    ;;
+esac
 
 if test -n "$NSPR_CFLAGS" -o -n "$NSPR_LIBS"; then
     ac_configure_args="$ac_configure_args --with-nspr-cflags='$NSPR_CFLAGS'"
diff --git a/python/mozbuild/mozbuild/action/generate_symbols_file.py b/python/mozbuild/mozbuild/action/generate_symbols_file.py
index ff6136bb14..3eebf324cc 100644
--- a/python/mozbuild/mozbuild/action/generate_symbols_file.py
+++ b/python/mozbuild/mozbuild/action/generate_symbols_file.py
@@ -83,6 +83,20 @@ def generate_symbols_file(output, *args):
         # };
         output.write('{\nglobal:\n  %s;\nlocal:\n  *;\n};'
                      % ';\n  '.join(symbols))
+    elif buildconfig.substs['OS_TARGET'] == 'SunOS':
+        # A linker version script is generated for Sun LD that looks like the
+        # following:
+        # $mapfile_version 2
+        # SYMBOL_VERSION SUNW_1.1 {
+        # global:
+        #   symbol1;
+        #   symbol2;
+        #   ...
+        # local:
+        #   *;
+        # };
+        output.write('$mapfile_version 2\nSYMBOL_VERSION SUNW_1.1 {\nglobal:\n  %s;\nlocal:\n  *;\n};'
+                     % ';\n  '.join(symbols))
     elif buildconfig.substs['OS_TARGET'] == 'Darwin':
         # A list of symbols is generated for Apple ld that simply lists all
         # symbols, with an underscore prefix.