Minor fixes to allow angle to build again.

Disable one compiler warning for undefined template value.
Use ::std::mutex for Lock on non-windows platforms.

Change-Id: I376301e606323489071f560bf37494e249d8e1e4
Tested: Run build-ANGLE.sh.
Signed-off-by: Kenneth Magic <kmagic@google.com>
diff --git a/src/libGLESv2.gypi b/src/libGLESv2.gypi
index e501c73..fb28566 100644
--- a/src/libGLESv2.gypi
+++ b/src/libGLESv2.gypi
@@ -558,6 +558,10 @@
         {
             'target_name': 'libANGLE',
             'type': 'static_library',
+            'cflags':
+            [
+                '-Wno-undefined-var-template',
+            ],
             'dependencies':
             [
                 'translator_static',
diff --git a/src/libGLESv2/global_state.h b/src/libGLESv2/global_state.h
index a167023..ffadd88 100644
--- a/src/libGLESv2/global_state.h
+++ b/src/libGLESv2/global_state.h
@@ -9,6 +9,7 @@
 #ifndef LIBGLESV2_GLOBALSTATE_H_
 #define LIBGLESV2_GLOBALSTATE_H_
 
+#include <mutex>
 #include <EGL/egl.h>
 
 namespace gl
@@ -22,6 +23,7 @@
 // specialized to Windows
 
 class ScopedLock;
+#ifdef ANGLE_PLATFORM_WINDOWS
 class Lock {
 public:
 	Lock() {
@@ -39,6 +41,9 @@
 private:
 	CRITICAL_SECTION mLock;
 };
+#else
+typedef ::std::mutex Lock;
+#endif
 
 class ScopedLock {
 public: