Using boost::regex, because g++ 4.8 doesn't have std::regex

CMakeLists.txt

@@ -3,4 +3,4 @@ cmake_minimum_required(VERSION 2.8)
 aux_source_directory(. SRC_LIST)
 add_executable(${PROJECT_NAME} ${SRC_LIST})
 target_compile_options(${PROJECT_NAME} PRIVATE -g -std=c++11)
-target_link_libraries(${PROJECT_NAME} poppler-cpp pthread boost_program_options)
+target_link_libraries(${PROJECT_NAME} poppler-cpp pthread boost_program_options boost_regex)

main.cpp

@@ -3,8 +3,8 @@
 #include <iostream>
 #include <string>
 #include <future>
-#include <regex>
 
+#include <boost/regex.hpp>
 #include <boost/program_options.hpp>
 #include <poppler/cpp/poppler-page.h>
 #include <poppler/cpp/poppler-document.h>
@@ -41,6 +41,9 @@ void render_pages(document *doc, int first, int last, int step, const string& fm
 
 bool validate_output(const string& output)
 {
+    using boost::regex;
+    using boost::sregex_iterator;
+
     if (output.empty()) {
         cout << "Output format must be specified" << endl;
         return false;