[flang] Add CMakeLists.txt and .gitignore

Original-commit: flang-compiler/f18@d9a1ea4c49
Tree-same-pre-rewrite: false

flang/.gitignore

@@ -0,0 +1,3 @@
+Debug
+Release
+tags

flang/CMakeLists.txt

@@ -0,0 +1,24 @@
+cmake_minimum_required(VERSION 3.9.0)
+project(f18)
+
+set(GCC /home/sw/thirdparty/gcc/gcc-7.3.0/linux86-64/redhat)
+set(CMAKE_CXX_COMPILER "${GCC}/bin/g++")
+set(CMAKE_INSTALL_RPATH "${GCC}/lib64")
+set(CMAKE_BUILD_WITH_INSTALL_RPATH true)
+
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -std=c++17")
+
+set(SOURCES
+  char-buffer.cc
+  f2018-demo.cc
+  idioms.cc
+  message.cc
+  parse-tree.cc
+  position.cc
+  preprocessor.cc
+  prescan.cc
+  source.cc
+)
+add_executable(f18 ${SOURCES})
+
+add_executable(type-test type.cc idioms.cc)