Build with the system NSPR library instead of the bundled version.

Originally based on this Debian patch:
https://salsa.debian.org/chromium-team/chromium/-/blob/master/debian/patches/system/nspr.patch

diff --git a/base/BUILD.gn b/base/BUILD.gn
--- a/base/BUILD.gn
+++ b/base/BUILD.gn
@@ -184,6 +184,12 @@ buildflag_header("ios_cronet_buildflags") {
   flags = [ "CRONET_BUILD=$is_cronet_build" ]
 }
 
+if (is_linux) {
+  ldflags = [
+    "-lnspr4",
+  ]
+}
+
 # Base and everything it depends on should be a static library rather than
 # a source set. Base is more of a "library" in the classic sense in that many
 # small parts of it are used in many different contexts. This combined with a
@@ -838,8 +844,6 @@ mixed_component("base") {
     "third_party/cityhash_v103/src/city_v103.cc",
     "third_party/cityhash_v103/src/city_v103.h",
     "third_party/icu/icu_utf.h",
-    "third_party/nspr/prtime.cc",
-    "third_party/nspr/prtime.h",
     "third_party/superfasthash/superfasthash.c",
     "thread_annotations.h",
     "threading/hang_watcher.cc",
diff --git a/base/time/pr_time_unittest.cc b/base/time/pr_time_unittest.cc
--- a/base/time/pr_time_unittest.cc
+++ b/base/time/pr_time_unittest.cc
@@ -6,7 +6,7 @@
 #include <time.h>
 
 #include "base/compiler_specific.h"
-#include "base/third_party/nspr/prtime.h"
+#include <nspr/prtime.h>
 #include "base/time/time.h"
 #include "build/build_config.h"
 #include "testing/gtest/include/gtest/gtest.h"
diff --git a/base/time/time.cc b/base/time/time.cc
--- a/base/time/time.cc
+++ b/base/time/time.cc
@@ -21,7 +21,7 @@
 #include <utility>
 
 #include "base/strings/stringprintf.h"
-#include "base/third_party/nspr/prtime.h"
+#include <nspr/prtime.h>
 #include "base/time/time_override.h"
 #include "build/build_config.h"
 #include "third_party/abseil-cpp/absl/types/optional.h"
 value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=fb3ac987c94e0a77b5c39913dace0b565afc3291'>root</a>/<a href='/guix/log/etc?id=fb3ac987c94e0a77b5c39913dace0b565afc3291'>etc</a>/<a href='/guix/log/etc/init.d?id=fb3ac987c94e0a77b5c39913dace0b565afc3291'>init.d</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/etc/init.d?id=fb3ac987c94e0a77b5c39913dace0b565afc3291&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2021-07-07 23:54:20 -0400'>2021-07-07</span></td><td><a href='/guix/commit/etc/init.d?id=4cbe0127a668cbcc64087c5d311308b59d39b104'>guix-install.sh: Prompt for configuring substitutes discovery.</a><span class='msg-avail'>...<span class='msg-tooltip'>Also ensure prompt_yes_no always print the message with a trailing space,
which is more pleasing to the eye.

* etc/guix-daemon.conf.in &lt;--discover=no&gt;: New guix-daemon option.
* etc/guix-daemon.service.in: Likewise.
* etc/init.d/guix-daemon.in: Likewise.
* etc/openrc/guix-daemon.in: Likewise.
* etc/guix-install.sh (configure_substitute_discovery): New procedure.
(sys_enable_guix_daemon): Ask the user whether automatic substitute discovery
should be enabled.  Set the '--discover' argument accordingly.
(prompt_yes_no): Add a trailing space to the message.
(sys_authorize_build_farms): Remove trailing space from the message argument.
* NEWS (Distribution): Add news.
</span></span></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2020-03-11 02:45:33 +0100'>2020-03-11</span></td><td><a href='/guix/commit/etc/init.d?id=73fbe04107d38f4561636c74d28d7a4935cbb1ef'>Add system start-up files for guix-daemon.</a><span class='msg-avail'>...<span class='msg-tooltip'>* etc/init.d/guix-daemon.in: New file.
* nix/local.mk (etc/init.d/guix-daemon): New rule.
(nodist_sysvinitservice_DATA): Add etc/init.d/guix-daemon.in .
(CLEANFILES): Add etc/init.d/guix-daemon .
* .gitignore: Add etc/init.d/guix-daemon .
</span></span></td><td>Danny Milosavljevic</td></tr>