Adding c++14 flag to msvc builds (#10754)

build_defs/cpp_opts.bzl

@@ -2,18 +2,19 @@
 
 COPTS = select({
     "//build_defs:config_msvc": [
-        "/wd4065",  # switch statement contains 'default' but no 'case' labels
-        "/wd4244",  # 'conversion' conversion from 'type1' to 'type2', possible loss of data
-        "/wd4251",  # 'identifier' : class 'type' needs to have dll-interface to be used by clients of class 'type2'
-        "/wd4267",  # 'var' : conversion from 'size_t' to 'type', possible loss of data
-        "/wd4305",  # 'identifier' : truncation from 'type1' to 'type2'
-        "/wd4307",  # 'operator' : integral constant overflow
-        "/wd4309",  # 'conversion' : truncation of constant value
-        "/wd4334",  # 'operator' : result of 32-bit shift implicitly converted to 64 bits (was 64-bit shift intended?)
-        "/wd4355",  # 'this' : used in base member initializer list
-        "/wd4506",  # no definition for inline function 'function'
-        "/wd4800",  # 'type' : forcing value to bool 'true' or 'false' (performance warning)
-        "/wd4996",  # The compiler encountered a deprecated declaration.
+        "/wd4065",    # switch statement contains 'default' but no 'case' labels
+        "/wd4244",    # 'conversion' conversion from 'type1' to 'type2', possible loss of data
+        "/wd4251",    # 'identifier' : class 'type' needs to have dll-interface to be used by clients of class 'type2'
+        "/wd4267",    # 'var' : conversion from 'size_t' to 'type', possible loss of data
+        "/wd4305",    # 'identifier' : truncation from 'type1' to 'type2'
+        "/wd4307",    # 'operator' : integral constant overflow
+        "/wd4309",    # 'conversion' : truncation of constant value
+        "/wd4334",    # 'operator' : result of 32-bit shift implicitly converted to 64 bits (was 64-bit shift intended?)
+        "/wd4355",    # 'this' : used in base member initializer list
+        "/wd4506",    # no definition for inline function 'function'
+        "/wd4800",    # 'type' : forcing value to bool 'true' or 'false' (performance warning)
+        "/wd4996",    # The compiler encountered a deprecated declaration.
+        "/std:c++14", # Use C++14
     ],
     "//conditions:default": [
         "-DHAVE_ZLIB",