fix build error with automake >=1.14
fix link error on freebsd
remove duplicated CFLAGS
fix compile error with clang
fix uninitialized value reference
replace --enable-native with --with-arch=native
update gitignore
fix build error on osx & refact
fix build error on osx
fix build error on osx
fix build error on osx
Merge branch 'release/0.7.0'
Merge branch 'release/0.7.0' into develop