[C99] Claim conformance to WG14 N631 and WG14 N696

Both of these relate to handling of standard pragmas. N631 is about
various STDC pragmas being included in the standard at all, and N696
is about whether macros are expanded in standard pragmas (they're not).

Author: AaronBallman

clang/test/C/C99/n696.c

@@ -0,0 +1,22 @@
+// RUN: %clang_cc1 -verify %s
+
+/* WG14 N696: yes
+ * Standard pragmas - improved wording
+ *
+ * NB: this also covers N631 which changed these features into pragmas rather
+ * than macros.
+ */
+
+// Verify that we do not expand macros in STDC pragmas. If we expanded them,
+// this code would issue diagnostics.
+#define ON 12
+#pragma STDC FENV_ACCESS ON
+#pragma STDC CX_LIMITED_RANGE ON
+#pragma STDC FP_CONTRACT ON
+
+// If we expanded macros, this code would not issue diagnostics.
+#define BLERP OFF
+#pragma STDC FENV_ACCESS BLERP      // expected-warning {{expected 'ON' or 'OFF' or 'DEFAULT' in pragma}}
+#pragma STDC CX_LIMITED_RANGE BLERP // expected-warning {{expected 'ON' or 'OFF' or 'DEFAULT' in pragma}}
+#pragma STDC FP_CONTRACT BLERP      // expected-warning {{expected 'ON' or 'OFF' or 'DEFAULT' in pragma}}
+

clang/www/c_status.html

@@ -330,11 +330,11 @@ <h2 id="c99">C99 implementation status</h2>
     </tr>
       <tr>
         <td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n631.htm">N631</a></td>
-        <td class="unknown" align="center">Unknown</td>
+        <td class="full" align="center">Yes</td>
       </tr>
       <tr>
         <td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n696.ps">N696</a></td>
-        <td class="unknown" align="center">Unknown</td>
+        <td class="full" align="center">Yes</td>
       </tr>
     <tr>
       <td>__func__ predefined identifier</td>