+ ],
+ ]
+];
+const ENV = [
+ "ubuntu-20.04" => [
+ "gnu" => [
+ "new" => [
+ "INSTALL_CC" => "gcc-10",
+ "INSTALL_CXX" => "g++-10",
+ ]
+ ],
+ "clang" => [
+ "new" => [
+ "CXXFLAGS" => "-stdlib=libc++"
+ ],
+ "cur" => [
+ "CXXFLAGS" => "-stdlib=libc++",
+ "INSTALL_CXX" => "libc++-9-dev libc++abi-9-dev"
+ ],
+ "old" => [
+ "CXXFLAGS" => "-stdlib=libc++",
+ "INSTALL_CXX" => "libc++-8-dev libc++abi-8-dev"
+ ],
+ ]
+ ],
+ "ubuntu-18.04" => [
+ "clang" => [
+ "new" => [
+ "CXXFLAGS" => "-stdlib=libc++"
+ ],
+ "cur" => [
+ "CXXFLAGS" => "-stdlib=libc++"
+ ],
+ "old" => [
+ "CXXFLAGS" => "-stdlib=libc++"
+ ],