cmake: write the build command itself with --verbose

Help/release/dev/cmake-verbose-print-build-tool-command.rst

@@ -0,0 +1,5 @@
+cmake-verbose-print-build-tool-command
+--------------------------------------
+
+* ``cmake --build $dir --verbose`` will now print the working directory and
+  command line used to perform the build.

Source/cmake.cxx

@@ -3699,10 +3699,19 @@ int cmake::Build(int jobs, std::string dir, std::vector<std::string> targets,
   }
 
   this->GlobalGenerator->PrintBuildCommandAdvice(std::cerr, jobs);
-  return this->GlobalGenerator->Build(
+  int buildresult = this->GlobalGenerator->Build(
     jobs, "", dir, projName, targets, output, "", config, buildOptions,
     verbose, cmDuration::zero(), cmSystemTools::OUTPUT_PASSTHROUGH,
     nativeOptions);
+
+  if (verbose) {
+    // `cmGlobalGenerator::Build` logs metadata about what directory and
+    // commands are being executed to the `output` parameter. If CMake is
+    // verbose, print this out.
+    std::cout << output;
+  }
+
+  return buildresult;
 }
 
 bool cmake::Open(const std::string& dir, bool dryRun)