Failed to compile rtags on ubuntu 18.04lts

[RaphaelTFool]

Describe the bug
Failed to compile rtags on ubuntu 18.04lts.

Scanning dependencies of target rtags
Scanning dependencies of target rct
[  1%] Building CXX object src/CMakeFiles/rct.dir/rct/rct/SHA256.cpp.o
[  2%] Building CXX object src/CMakeFiles/rct.dir/rct/rct/Buffer.cpp.o
[  4%] Building CXX object src/CMakeFiles/rct.dir/rct/rct/AES256CBC.cpp.o
[  5%] Building CXX object src/CMakeFiles/rtags.dir/ClangIndexer.cpp.o
[  6%] Building CXX object src/CMakeFiles/rtags.dir/ClangThread.cpp.o
[  8%] Building CXX object src/CMakeFiles/rct.dir/rct/rct/Config.cpp.o
[  9%] Building CXX object src/CMakeFiles/rct.dir/rct/rct/Connection.cpp.o
[ 11%] Building CXX object src/CMakeFiles/rct.dir/rct/rct/CpuUsage.cpp.o
[ 12%] Building CXX object src/CMakeFiles/rct.dir/rct/rct/Date.cpp.o
[ 13%] Building CXX object src/CMakeFiles/rct.dir/rct/rct/EventLoop.cpp.o
In file included from /home/raphael/github/rtags/src/rct/rct/EventLoop.h:4,
                 from /home/raphael/github/rtags/src/rct/rct/EventLoop.cpp:1:
/home/raphael/github/rtags/src/rct/rct/Apply.h:9:10: error: ‘size_t’ has not been declared
    9 | template<size_t N>
      |          ^~~~~~
/home/raphael/github/rtags/src/rct/rct/Apply.h:13:27: error: ‘N’ was not declared in this scope
   13 |         -> decltype(Apply<N-1>::apply(
      |                           ^
/home/raphael/github/rtags/src/rct/rct/Apply.h:13:30: error: template argument 1 is invalid
   13 |         -> decltype(Apply<N-1>::apply(
      |                              ^
/home/raphael/github/rtags/src/rct/rct/Apply.h:15:50: error: ‘N’ was not declared in this scope
   15 |                                       ::std::get<N-1>(::std::forward<T>(t)), ::std::forward<A>(a)...
      |                                                  ^
/home/raphael/github/rtags/src/rct/rct/Apply.h:46:10: error: ‘size_t’ has not been declared
   46 | template<size_t N>
      |          ^~~~~~
/home/raphael/github/rtags/src/rct/rct/Apply.h:50:31: error: ‘N’ was not declared in this scope
   50 |         -> decltype(ApplyMove<N-1>::applyMove(
      |                               ^
/home/raphael/github/rtags/src/rct/rct/Apply.h:50:34: error: template argument 1 is invalid
   50 |         -> decltype(ApplyMove<N-1>::applyMove(
      |                                  ^
/home/raphael/github/rtags/src/rct/rct/Apply.h:52:58: error: ‘N’ was not declared in this scope
   52 |                                               ::std::get<N-1>(::std::forward<T>(t)), ::std::forward<A>(a)...
      |                                                          ^
[ 15%] Building CXX object src/CMakeFiles/rct.dir/rct/rct/FileSystemWatcher.cpp.o
src/CMakeFiles/rct.dir/build.make:172: recipe for target 'src/CMakeFiles/rct.dir/rct/rct/EventLoop.cpp.o' failed
make[2]: *** [src/CMakeFiles/rct.dir/rct/rct/EventLoop.cpp.o] Error 1
make[2]: *** Waiting for unfinished jobs....
[ 16%] Building CXX object src/CMakeFiles/rtags.dir/ClassHierarchyJob.cpp.o
^Csrc/CMakeFiles/rtags.dir/build.make:81: recipe for target 'src/CMakeFiles/rtags.dir/ClangIndexer.cpp.o' failed
make[2]: *** [src/CMakeFiles/rtags.dir/ClangIndexer.cpp.o] Interrupt
src/CMakeFiles/rtags.dir/build.make:107: recipe for target 'src/CMakeFiles/rtags.dir/ClassHierarchyJob.cpp.o' failed
make[2]: *** [src/CMakeFiles/rtags.dir/ClassHierarchyJob.cpp.o] Interrupt
make[2]: *** wait: No child processes.  Stop.
src/CMakeFiles/rtags.dir/build.make:94: recipe for target 'src/CMakeFiles/rtags.dir/ClangThread.cpp.o' failed
make[2]: *** [src/CMakeFiles/rtags.dir/ClangThread.cpp.o] Interrupt
CMakeFiles/Makefile2:1128: recipe for target 'src/CMakeFiles/rtags.dir/all' failed
make[1]: *** [src/CMakeFiles/rtags.dir/all] Interrupt
make[1]: *** wait: No child processes.  Stop.
make[1]: *** Waiting for unfinished jobs....
make[1]: *** wait: No child processes.  Stop.
Makefile:159: recipe for target 'all' failed
make: *** [all] Error 2

Environment (please complete the following information):

• OS/Version: [Ubuntu 18.04.5 LTS]
• RTags(rdm,rc): [git clone latest]
• Emacs: [e.g. 25.2.2]
• LLVM/Clang: [9 and 4.9 tried]

Additional context
Finally, I download the 2.38 release tarball and compile it successfully.

[alan717]

I had the same compile error with latest commit,just modify size_twithstd::size_t that work !

[RaphaelTFool]

I had the same compile error with latest commit,just modify size_twithstd::size_t that work !

Thanks， It really works！