diff --git a/include/cxx/cmath b/include/cxx/cmath
index c6711b6aba..589ff40ff9 100644
--- a/include/cxx/cmath
+++ b/include/cxx/cmath
@@ -30,6 +30,12 @@
 
 #include <math.h>
 
+#undef signbit
+#undef fpclassify
+#undef isfinite
+#undef isinf
+#undef isnan
+
 //***************************************************************************
 // Namespace
 //***************************************************************************
@@ -54,6 +60,7 @@ namespace std
   using ::frexpf;
   using ::ldexpf;
   using ::logf;
+  using ::log1pf;
   using ::log10f;
   using ::log2f;
   using ::modff;
@@ -66,6 +73,29 @@ namespace std
   using ::tanhf;
   using ::gamma;
   using ::lgamma;
+
+  constexpr bool
+  signbit(float __x)
+  { return __builtin_signbit(__x); }
+
+  constexpr int 
+  fpclassify(float __x)
+  { return __builtin_fpclassify(FP_NAN, FP_INFINITE, FP_NORMAL,
+				FP_SUBNORMAL, FP_ZERO, __x); }
+
+  constexpr bool
+  isfinite(float __x)
+  { return __builtin_isfinite(__x); }
+
+  constexpr bool
+  isinf(float __x)
+  { return __builtin_isinf(__x); }
+
+  constexpr bool
+  isnan(float __x)
+  { return __builtin_isnan(__x); }
+
+
 #endif
 
 #ifdef CONFIG_HAVE_DOUBLE
@@ -83,6 +113,7 @@ namespace std
   using ::frexp;
   using ::ldexp;
   using ::log;
+  using ::log1p;
   using ::log10;
   using ::log2;
   using ::modf;
@@ -93,6 +124,28 @@ namespace std
   using ::sqrt;
   using ::tan;
   using ::tanh;
+
+  constexpr bool
+  signbit(double __x)
+  { return __builtin_signbit(__x); }
+
+  constexpr int 
+  fpclassify(double __x)
+  { return __builtin_fpclassify(FP_NAN, FP_INFINITE, FP_NORMAL,
+		FP_SUBNORMAL, FP_ZERO, __x); }
+
+  constexpr bool
+  isfinite(double __x)
+  { return __builtin_isfinite(__x); }
+
+  constexpr bool
+  isinf(double __x)
+  { return __builtin_isinf(__x); }
+
+  constexpr bool
+  isnan(double __x)
+  { return __builtin_isnan(__x); }
+
 #endif
 
 #ifdef CONFIG_HAVE_LONG_DOUBLE
@@ -110,6 +163,7 @@ namespace std
   using ::frexpl;
   using ::ldexpl;
   using ::logl;
+  using ::log1pl;
   using ::log10l;
   using ::log2l;
   using ::modfl;
@@ -120,6 +174,28 @@ namespace std
   using ::sqrtl;
   using ::tanl;
   using ::tanhl;
+
+  constexpr bool
+  signbit(long double __x)
+  { return __builtin_signbit(__x); }
+
+  constexpr int 
+  fpclassify(long double __x)
+  { return __builtin_fpclassify(FP_NAN, FP_INFINITE, FP_NORMAL,
+		FP_SUBNORMAL, FP_ZERO, __x); }
+
+  constexpr bool
+  isfinite(long double __x)
+  { return __builtin_isfinite(__x); }
+
+  constexpr bool
+  isinf(long double __x)
+  { return __builtin_isinf(__x); }
+
+  constexpr bool
+  isnan(long double __x)
+  { return __builtin_isnan(__x); }
+
 #endif
 
 }
diff --git a/include/cxx/cstdarg b/include/cxx/cstdarg
index 8725369f1a..d8456d3f0f 100644
--- a/include/cxx/cstdarg
+++ b/include/cxx/cstdarg
@@ -27,8 +27,14 @@
 
 #include <stdarg.h>
 
+
 //***************************************************************************
 // Namespace
 //***************************************************************************
 
+namespace std
+{
+  using ::va_list;
+}
+
 #endif // __INCLUDE_CXX_CSTDARG
diff --git a/include/cxx/ctime b/include/cxx/ctime
index 3f00c087fd..ae4f14f280 100644
--- a/include/cxx/ctime
+++ b/include/cxx/ctime
@@ -45,6 +45,8 @@ namespace std
   using ::clock_gettime;
   using ::mktime;
   using ::gmtime_r;
+  using ::gmtime;
+  using ::strftime;
   using ::timer_create;
   using ::timer_delete;
   using ::timer_settime;