Fixed completion_string_test on Linux

tests/completion_string_test.cc

@@ -1,6 +1,7 @@
 #include "clangmm.h"
 #include <string>
 #include <cassert>
+#include <regex>
 
 int main() {
   {
@@ -14,8 +15,18 @@ int main() {
     std::string tests_path=LIBCLANGMM_TESTS_PATH;
     std::string path(tests_path+"/case/main.cpp");
   
+    std::vector<std::string> arguments;
+    auto clang_version_string=clangmm::to_string(clang_getClangVersion());
+    const static std::regex clang_version_regex("^[A-Za-z ]+([0-9.]+).*$");
+    std::smatch sm;
+    if(std::regex_match(clang_version_string, sm, clang_version_regex)) {
+      auto clang_version=sm[1].str();
+      arguments.emplace_back("-I/usr/lib/clang/"+clang_version+"/include");
+      arguments.emplace_back("-I/usr/lib64/clang/"+clang_version+"/include"); // For Fedora
+    }
+  
     clangmm::Index index(0, 0);
-    clangmm::TranslationUnit tu(index, path, {});
+    clangmm::TranslationUnit tu(index, path, arguments);
   
     std::string buffer="#include <string>\n"
                        "int main(int argc, char *argv[]) {\n"