Fix some build errors due to static assert change
diff --git a/docs/migration.md b/docs/migration.md
index f781276..ff4f445 100644
--- a/docs/migration.md
+++ b/docs/migration.md
@@ -40,13 +40,11 @@
 supported already in C99 but does not work with every compiler and can
 produce confusing error messages.
 
-**Changes:** Now `_Static_assert` is used by default. If preferred, the
-old default behavior can be restored by defining `PB_C99_STATIC_ASSERT`
-in `pb.h` or on compiler command line.
+**Changes:** Now `_Static_assert` is used by default.
 
 **Required actions:** If the keyword is not recognized, set the compiler to
 C11 standard mode if available. If it is not available, define either `PB_C99_STATIC_ASSERT`
-or `PB_NO_STATIC_ASSERT`.
+or `PB_NO_STATIC_ASSERT` in `pb.h` or on compiler command line.
 
 **Error indications:** "`Undefined identifier _Static_assert`
 
diff --git a/pb.h b/pb.h
index 01320c7..5aa17ae 100644
--- a/pb.h
+++ b/pb.h
@@ -52,6 +52,11 @@
  * Normally it is automatically detected based on __BYTE_ORDER__ macro. */
 /* #define PB_LITTLE_ENDIAN_8BIT 1 */
 
+/* Configure static assert mechanism. Instead of changing these, set your
+ * compiler to C11 standard mode if possible. */
+/* #define PB_C99_STATIC_ASSERT 1 */
+/* #define PB_NO_STATIC_ASSERT 1 */
+
 /******************************************************************
  * You usually don't need to change anything below this line.     *
  * Feel free to look around and use the defined macros, though.   *
@@ -183,7 +188,12 @@
 #  define PB_STATIC_ASSERT(COND,MSG)
 #endif
 
-/* Test that PB_STATIC_ASSERT works */
+/* Test that PB_STATIC_ASSERT works
+ * If you get errors here, you may need to do one of these:
+ * - Enable C11 standard support in your compiler
+ * - Define PB_C99_STATIC_ASSERT to enable C99 standard support
+ * - Define PB_NO_STATIC_ASSERT to disable static asserts altogether
+ */
 PB_STATIC_ASSERT(1, STATIC_ASSERT_IS_NOT_WORKING)
 
 /* Number of required fields to keep track of. */
diff --git a/tests/SConstruct b/tests/SConstruct
index 0c17460..d2af0d7 100644
--- a/tests/SConstruct
+++ b/tests/SConstruct
@@ -207,7 +207,7 @@
     if 'clang' in env['CXX']:
         env.Append(CXXFLAGS = '-g -Wall -Werror -Wextra -Wno-missing-field-initializers')
     elif 'g++' in env['CXX'] or 'gcc' in env['CXX']:
-        env.Append(CXXFLAGS = '-g -Wall -Werror -Wextra -Wno-missing-field-initializers')
+        env.Append(CXXFLAGS = '-g -Wall -Werror -Wextra -Wno-missing-field-initializers -std=gnu++11')
     elif 'cl' in env['CXX']:
         env.Append(CXXFLAGS = '/Zi /W2 /WX /wd4116 /wd4127')