Ninja: don't use shell when cmake is called directly

When linking with cmake and vs_link_* the command line
could be too long for cmd.exe, which needs not to be
called in this case. (was not cached by a test)

Introduce rules which don't use the shell and use this
rule when there are no pre or post step.

For free we get a small speedup, because cmd is then
not called.

Also be more accurate when estimating the
command line length.

1 files changed, 9 insertions, 1 deletions

diff --git a/Source/cmGlobalNinjaGenerator.cxx b/Source/cmGlobalNinjaGenerator.cxx
index 11d8653..2c00e06 100644
--- a/Source/cmGlobalNinjaGenerator.cxx
+++ b/Source/cmGlobalNinjaGenerator.cxx
@@ -106,6 +106,7 @@ void cmGlobalNinjaGenerator::WriteBuild(std::ostream& os,
                                         const cmNinjaDeps& implicitDeps,
                                         const cmNinjaDeps& orderOnlyDeps,
                                         const cmNinjaVars& variables,
+                                        bool suppressShell,
                                         int cmdLineLimit)
 {
   // Make sure there is a rule.
@@ -177,8 +178,15 @@ void cmGlobalNinjaGenerator::WriteBuild(std::ostream& os,
 
   // check if a response file rule should be used
   const std::string args = arguments.str();
-  if (cmdLineLimit > 0 && args.size() > (size_t)cmdLineLimit)
+  if (suppressShell)
+    {
+    builds << "_NOSHELL";
+    }
+  else if (cmdLineLimit > 0 &&
+      args.size() + builds.str().size() > (size_t)cmdLineLimit)
+    {
     builds << "_RSPFILE";
+    }
 
   os << builds.str() << args;