Compiling ESR 31 is broken with mingw-w64 based on GCC 4.8.3

We get:

/home/ubuntu/build/tor-browser/mozglue/build/WindowsDllBlocklist.cpp: In static member function 'static void {anonymous}::DllBlockSet::Write(HANDLE)':
/home/ubuntu/build/tor-browser/mozglue/build/WindowsDllBlocklist.cpp:422:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
       if (b->mVersion != -1) {
                           ^
/home/ubuntu/build/tor-browser/mozglue/build/WindowsDllBlocklist.cpp: In function 'NTSTATUS {anonymous}::patched_LdrLoadDll(PWCHAR, PULONG, PUNICODE_STRING, PHANDLE)':
/home/ubuntu/build/tor-browser/mozglue/build/WindowsDllBlocklist.cpp:645:1: error: jump to label 'continue_loading' [-fpermissive]
 continue_loading:
 ^
/home/ubuntu/build/tor-browser/mozglue/build/WindowsDllBlocklist.cpp:538:12: error:   from here [-fpermissive]
       goto continue_loading;
            ^
/home/ubuntu/build/tor-browser/mozglue/build/WindowsDllBlocklist.cpp:556:10: error:   crosses initialization of 'char* dot'
   char * dot = strchr(dllName, '.');
          ^
/home/ubuntu/build/tor-browser/mozglue/build/WindowsDllBlocklist.cpp:645:1: error: jump to label 'continue_loading' [-fpermissive]
 continue_loading:
 ^
/home/ubuntu/build/tor-browser/mozglue/build/WindowsDllBlocklist.cpp:528:10: error:   from here [-fpermissive]
     goto continue_loading;
          ^
/home/ubuntu/build/tor-browser/mozglue/build/WindowsDllBlocklist.cpp:556:10: error:   crosses initialization of 'char* dot'
   char * dot = strchr(dllName, '.');
          ^
/home/ubuntu/build/tor-browser/mozglue/build/WindowsDllBlocklist.cpp:645:1: error: jump to label 'continue_loading' [-fpermissive]
 continue_loading:
 ^
/home/ubuntu/build/tor-browser/mozglue/build/WindowsDllBlocklist.cpp:506:10: error:   from here [-fpermissive]
     goto continue_loading;
          ^
/home/ubuntu/build/tor-browser/mozglue/build/WindowsDllBlocklist.cpp:556:10: error:   crosses initialization of 'char* dot'
   char * dot = strchr(dllName, '.');
          ^