From: Hans Petter Jansson <hpj@copyleft.no>
      Wolfgang Rosenauer <wr@rosenauer.org>
Subject: use libnsssharedhelper if available at compile time
         (can be disabled by exporting MOZ_XRE_NO_NSSHELPER=1)
References:

diff --git a/configure.in b/configure.in
--- a/configure.in
+++ b/configure.in
@@ -7987,16 +7987,31 @@ AC_SUBST(QCMS_LIBS)
 
 dnl ========================================================
 dnl HarfBuzz
 dnl ========================================================
 MOZ_HARFBUZZ_LIBS='$(DEPTH)/gfx/harfbuzz/src/$(LIB_PREFIX)mozharfbuzz.$(LIB_SUFFIX)'
 AC_SUBST(MOZ_HARFBUZZ_LIBS)
 
 dnl ========================================================
+dnl Check for nss-shared-helper
+dnl ========================================================
+
+  PKG_CHECK_MODULES(NSSHELPER, nss-shared-helper,
+    [MOZ_ENABLE_NSSHELPER=1],
+    [MOZ_ENABLE_NSSHELPER=])
+
+if test "$MOZ_ENABLE_NSSHELPER"; then
+  AC_DEFINE(MOZ_ENABLE_NSSHELPER)
+fi
+AC_SUBST(MOZ_ENABLE_NSSHELPER)
+AC_SUBST(NSSHELPER_CFLAGS)
+AC_SUBST(NSSHELPER_LIBS)
+
+dnl ========================================================
 dnl SIL Graphite
 dnl ========================================================
 if test "$MOZ_GRAPHITE"; then
   MOZ_GRAPHITE_LIBS='$(DEPTH)/gfx/graphite2/src/$(LIB_PREFIX)mozgraphite2.$(LIB_SUFFIX)'
   AC_DEFINE(MOZ_GRAPHITE)
 else
   MOZ_GRAPHITE_LIBS=
 fi
diff --git a/security/manager/ssl/src/Makefile.in b/security/manager/ssl/src/Makefile.in
--- a/security/manager/ssl/src/Makefile.in
+++ b/security/manager/ssl/src/Makefile.in
@@ -90,12 +90,14 @@ DEFINES += \
   $(NULL)
 
 EXPORTS += \
   nsNSSShutDown.h \
   $(NULL)
 
 # Use local includes because they are inserted before INCLUDES
 # so that Mozilla's nss.h is used, not glibc's
-LOCAL_INCLUDES += $(NSS_CFLAGS)
+LOCAL_INCLUDES += $(NSS_CFLAGS) $(NSSHELPER_CFLAGS)
+
+EXTRA_DSO_LDOPTS += $(NSSHELPER_LIBS)
 
 include $(topsrcdir)/config/rules.mk
 
diff --git a/security/manager/ssl/src/nsNSSComponent.cpp b/security/manager/ssl/src/nsNSSComponent.cpp
--- a/security/manager/ssl/src/nsNSSComponent.cpp
+++ b/security/manager/ssl/src/nsNSSComponent.cpp
@@ -1,14 +1,21 @@
 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
  *
  * This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+#ifdef MOZ_ENABLE_NSSHELPER
+#pragma GCC visibility push(default)
+#include <nss-shared-helper.h>
+#pragma GCC visibility pop
+#include "prenv.h"
+#endif
+
 #include "nsNSSComponent.h"
 #include "nsNSSCallbacks.h"
 #include "nsNSSIOLayer.h"
 #include "nsCertVerificationThread.h"
 
 #include "nsNetUtil.h"
 #include "nsAppDirectoryServiceDefs.h"
 #include "nsDirectoryService.h"
@@ -1731,18 +1738,34 @@ nsNSSComponent::InitializeNSS(bool showW
     ConfigureInternalPKCS11Token();
 
     // The NSS_INIT_NOROOTINIT flag turns off the loading of the root certs
     // module by NSS_Initialize because we will load it in InstallLoadableRoots
     // later.  It also allows us to work around a bug in the system NSS in
     // Ubuntu 8.04, which loads any nonexistent "<configdir>/libnssckbi.so" as
     // "/usr/lib/nss/libnssckbi.so".
     uint32_t init_flags = NSS_INIT_NOROOTINIT | NSS_INIT_OPTIMIZESPACE;
-    SECStatus init_rv = ::NSS_Initialize(profileStr.get(), "", "",
-                                         SECMOD_DB, init_flags);
+    SECStatus init_rv = SECFailure;
+#ifdef MOZ_ENABLE_NSSHELPER
+    if (PR_GetEnv("MOZ_TB_NO_NSSHELPER")) {
+      init_rv = ::NSS_Initialize(profileStr.get(), "", "",
+                                 SECMOD_DB, init_flags);
+    } else {
+      init_rv = ::nsshelp_open_db ("Thunderbird", profileStr.get(), init_flags);
+
+      if (init_rv != SECSuccess) {
+        PR_LOG(gPIPNSSLog, PR_LOG_DEBUG, ("can not init NSS using nsshelp_open_db in %s\n", profileStr.get()));
+        init_rv = ::NSS_Initialize(profileStr.get(), "", "",
+                                   SECMOD_DB, init_flags);
+      }
+    }
+#else
+    init_rv = ::NSS_Initialize(profileStr.get(), "", "",
+                               SECMOD_DB, init_flags);
+#endif
 
     if (init_rv != SECSuccess) {
       PR_LOG(gPIPNSSLog, PR_LOG_DEBUG, ("can not init NSS r/w in %s\n", profileStr.get()));
 
       if (supress_warning_preference) {
         which_nss_problem = problem_none;
       }
       else {
diff --git a/toolkit/library/Makefile.in b/toolkit/library/Makefile.in
--- a/toolkit/library/Makefile.in
+++ b/toolkit/library/Makefile.in
@@ -443,17 +443,17 @@ EXTRA_DSO_LDOPTS += -INCREMENTAL:NO
 endif
 endif
 endif
 
 EXTRA_DSO_LDOPTS += $(LIBS_DIR) $(EXTRA_DSO_LIBS)
 
 DEFINES += -DIMPL_XREAPI
 
-EXTRA_DSO_LDOPTS += $(NSPR_LIBS) $(MOZALLOC_LIB)
+EXTRA_DSO_LDOPTS += $(NSPR_LIBS) $(MOZALLOC_LIB) $(NSSHELPER_LIBS)
 
 ifeq ($(MOZ_WIDGET_TOOLKIT),cocoa)
 CXXFLAGS += $(TK_CFLAGS)
 OS_LIBS += \
   -framework SystemConfiguration \
   -framework QTKit \
   -framework IOKit \
   -F/System/Library/PrivateFrameworks -framework CoreUI \