Apply '-march=native' in all non-Power architectures

Author: mofeing

configure.ac

@@ -11,10 +11,10 @@ AC_PROG_CXX
 
 # Default CXXFLAGS.
 CXXFLAGS="-O3  -std=c++17  -Wall -Wpedantic -Wno-unused-command-line-argument "$CXXFLAGS
-if test $(uname -m) == "x86_64"; then
-  CXXFLAGS="-march=native "$CXXFLAGS
-elif test $(uname -m) == "ppc64le" || test $(uname -m) == "ppc64"; then
+if test $(uname -m) == "ppc64le" || test $(uname -m) == "ppc64"; then
   CXXFLAGS="-mcpu=native "$CXXFLAGS
+else
+  CXXFLAGS="-march=native "$CXXFLAGS
 fi
 
 # Default LIBS