Fix GCC warnings

Author: mborland

include/boost/math/special_functions/powm1.hpp

@@ -64,10 +64,8 @@ BOOST_MATH_GPU_ENABLED inline T powm1_imp_dispatch(const T x, const T y, const P
       if (boost::math::trunc(y / 2) == y / 2)
          return powm1_imp(T(-x), T(y), pol);
    }
-   else
-   {
-      return powm1_imp(T(x), T(y), pol);
-   }
+
+   return powm1_imp(T(x), T(y), pol);
 }
 
 } // detail

test/test_erf.cpp

@@ -12,8 +12,8 @@
 #  pragma clang diagnostic push 
 #  pragma clang diagnostic ignored "-Wliteral-range"
 #elif defined(__GNUC__)
-#  pragma gcc diagnostic push 
-#  pragma gcc diagnostic ignored "-Wliteral-range"
+#  pragma GCC diagnostic push 
+#  pragma GCC diagnostic ignored "-Wliteral-range"
 #endif
 
 #include <boost/math/special_functions/erf.hpp>

test/test_mapairy.cpp

@@ -8,8 +8,8 @@
 #  pragma clang diagnostic push 
 #  pragma clang diagnostic ignored "-Wliteral-range"
 #elif defined(__GNUC__)
-#  pragma gcc diagnostic push 
-#  pragma gcc diagnostic ignored "-Wliteral-range"
+#  pragma GCC diagnostic push 
+#  pragma GCC diagnostic ignored "-Wliteral-range"
 #endif
 
 #define BOOST_TEST_MAIN