build: date now compiled alongside version

This should at the very least ensure that any changes to the git version
will trigger an update of the build date reported. Also ensure all dates
reported reference the same variable, rather than each reporting
potentially different __DATE__ macros.

build

@@ -1106,6 +1106,7 @@ update_git_version (mrtrix_dir[-1], os.path.join (lib_dir, 'version.cpp'), '''
 namespace MR {
   namespace App {
     const char* mrtrix_version = "%%%";
+    const char* build_date = __DATE__;
   }
 }
 ''')

core/app.cpp

@@ -83,7 +83,6 @@ namespace MR
     bool terminal_use_colour = true;
 
     const char* project_version = nullptr;
-    const char* build_date = __DATE__;
 
     int argc = 0;
     const char* const* argv = nullptr;
@@ -564,7 +563,7 @@ namespace MR
     {
       std::string version =
         "== " + App::NAME + " " + ( project_version ? project_version : mrtrix_version ) + " ==\n" +
-        str(8*sizeof (size_t)) + " bit " + MRTRIX_BUILD_TYPE + ", built " __DATE__
+        str(8*sizeof (size_t)) + " bit " + MRTRIX_BUILD_TYPE + ", built " + build_date
         + ( project_version ? std::string(" against MRtrix ") + mrtrix_version : std::string("") )
         + ", using Eigen " + str(EIGEN_WORLD_VERSION) + "." + str(EIGEN_MAJOR_VERSION) + "." + str(EIGEN_MINOR_VERSION) + "\n"
         "Author(s): " + AUTHOR + "\n" +

core/command.h

@@ -27,7 +27,6 @@
 
 extern "C" void R_main (int* cmdline_argc, char** cmdline_argv)
 {
-  ::MR::App::build_date = __DATE__;
 #ifdef MRTRIX_PROJECT_VERSION
   ::MR::App::project_version = MRTRIX_PROJECT_VERSION;
 #endif
@@ -75,7 +74,6 @@ int main (int cmdline_argc, char** cmdline_argv)
   mxcsr |= (1<<6); // denormals-are-zero
   _mm_setcsr (mxcsr);
 #endif
-  ::MR::App::build_date = __DATE__;
 #ifdef MRTRIX_PROJECT_VERSION
   ::MR::App::project_version = MRTRIX_PROJECT_VERSION;
 #endif