Revise C++ coding style using clang-format-6.0

Run the `clang-format.bash` script to update all our C and C++ code to a
new style defined by `.clang-format`.  Use `clang-format` version 6.0.

* If you reached this commit for a line in `git blame`, re-run the blame
  operation starting at the parent of this commit to see older history
  for the content.

* See the parent commit for instructions to rebase a change across this
  style transition commit.

Tests/GeneratorExpression/CMP0044/cmp0044-check.cpp

@@ -1,24 +1,24 @@
 
 #ifdef Type_Is_
-#if !Result
-#error Result should be 1 in WARN mode
-#endif
+#  if !Result
+#    error Result should be 1 in WARN mode
+#  endif
 #endif
 
 #ifdef Type_Is_NEW
-#if Result
-#error Result should be 0 in NEW mode
-#endif
+#  if Result
+#    error Result should be 0 in NEW mode
+#  endif
 #endif
 
 #ifdef Type_Is_OLD
-#if !Result
-#error Result should be 1 in OLD mode
-#endif
+#  if !Result
+#    error Result should be 1 in OLD mode
+#  endif
 #endif
 
 #if !defined(Type_Is_) && !defined(Type_Is_OLD) && !defined(Type_Is_NEW)
-#error No expected definition present
+#  error No expected definition present
 #endif
 
 void foo(void)

Tests/GeneratorExpression/pwd.c

@@ -3,11 +3,11 @@
 #include <stdlib.h>
 
 #ifdef _WIN32
-#include <direct.h>
-#define getcurdir _getcwd
+#  include <direct.h>
+#  define getcurdir _getcwd
 #else
-#include <unistd.h>
-#define getcurdir getcwd
+#  include <unistd.h>
+#  define getcurdir getcwd
 #endif
 
 int main(int argc, char* argv[])