diff --git a/GNUmakefile b/GNUmakefile
index c5d7138f..e013db84 100755
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -44,18 +44,18 @@ IS_SPARC64 := $(shell uname -m | $(GREP) -i -c "sparc64")
 IS_AIX := $(shell uname -s | $(GREP) -i -c 'aix')
 IS_SUN := $(shell uname -s | $(GREP) -i -c "SunOS")
 
-IS_LINUX := $(shell $(CXX) -dumpmachine 2>&1 | $(GREP) -i -c "Linux")
-IS_MINGW := $(shell $(CXX) -dumpmachine 2>&1 | $(GREP) -i -c "MinGW")
-IS_CYGWIN := $(shell $(CXX) -dumpmachine 2>&1 | $(GREP) -i -c "Cygwin")
-IS_DARWIN := $(shell $(CXX) -dumpmachine 2>&1 | $(GREP) -i -c "Darwin")
-IS_NETBSD := $(shell $(CXX) -dumpmachine 2>&1 | $(GREP) -i -c "NetBSD")
+IS_LINUX := $(shell $(CXX) -dumpmachine 2>/dev/null | $(GREP) -i -c "Linux")
+IS_MINGW := $(shell $(CXX) -dumpmachine 2>/dev/null | $(GREP) -i -c "MinGW")
+IS_CYGWIN := $(shell $(CXX) -dumpmachine 2>/dev/null | $(GREP) -i -c "Cygwin")
+IS_DARWIN := $(shell $(CXX) -dumpmachine 2>/dev/null | $(GREP) -i -c "Darwin")
+IS_NETBSD := $(shell $(CXX) -dumpmachine 2>/dev/null | $(GREP) -i -c "NetBSD")
 
-SUN_COMPILER := $(shell $(CXX) -V 2>&1 | $(GREP) -i -c -E 'CC: (Sun|Studio)')
-GCC_COMPILER := $(shell $(CXX) --version 2>&1 | $(GREP) -v -E '(llvm|clang)' | $(GREP) -i -c -E '(gcc|g\+\+)')
-XLC_COMPILER := $(shell $(CXX) $(CXX) -qversion 2>&1 |$(GREP) -i -c "IBM XL")
-CLANG_COMPILER := $(shell $(CXX) --version 2>&1 | $(GREP) -i -c -E '(llvm|clang)')
-INTEL_COMPILER := $(shell $(CXX) --version 2>&1 | $(GREP) -i -c '\(icc\)')
-MACPORTS_COMPILER := $(shell $(CXX) --version 2>&1 | $(GREP) -i -c "macports")
+SUN_COMPILER := $(shell $(CXX) -V 2>/dev/null | $(GREP) -i -c -E 'CC: (Sun|Studio)')
+GCC_COMPILER := $(shell $(CXX) --version 2>/dev/null | $(GREP) -v -E '(llvm|clang)' | $(GREP) -i -c -E '(gcc|g\+\+)')
+XLC_COMPILER := $(shell $(CXX) $(CXX) -qversion 2>/dev/null |$(GREP) -i -c "IBM XL")
+CLANG_COMPILER := $(shell $(CXX) --version 2>/dev/null | $(GREP) -i -c -E '(llvm|clang)')
+INTEL_COMPILER := $(shell $(CXX) --version 2>/dev/null | $(GREP) -i -c '\(icc\)')
+MACPORTS_COMPILER := $(shell $(CXX) --version 2>/dev/null | $(GREP) -i -c "macports")
 
 # Sun Studio 12.0 provides SunCC 0x0510; and Sun Studio 12.3 provides SunCC 0x0512
 SUNCC_510_OR_LATER := $(shell $(CXX) -V 2>&1 | $(GREP) -i -c -E "CC: (Sun|Studio) .* (5\.1[0-9]|5\.[2-9]|6\.)")