Add missing headers required for GCC 11 compilation

src/cmake.cpp

@@ -7,6 +7,7 @@
 #include "utility.hpp"
 #include <boost/algorithm/string.hpp>
 #include <boost/optional.hpp>
+#include <fstream>
 #include <future>
 #include <regex>
 

src/meson.cpp

@@ -7,6 +7,7 @@
 #include "terminal.hpp"
 #include "utility.hpp"
 #include <boost/optional.hpp>
+#include <fstream>
 #include <future>
 #include <regex>
 

src/project_build.cpp

@@ -4,6 +4,7 @@
 #include "json.hpp"
 #include "terminal.hpp"
 #include <boost/algorithm/string.hpp>
+#include <fstream>
 #include <regex>
 
 std::unique_ptr<Project::Build> Project::Build::create(const boost::filesystem::path &path) {