QNX: Introduce QCC compiler id for that QNX platform compiler.

Introduce policy CMP0047 to control resetting the id for
compatibility.

De-duplicate content in the QNX platform file by including the GNU
one. QNX is a form of GNU platform.

Do not clear CMAKE_SHARED_LIBRARY_${lang}_FLAGS variables.  They
are populated again later by the Compiler/GNU.cmake file anyway.

Modify the CMAKE_CXX_COMPILE_OBJECT variable only when the QCC
compiler id is in use, and the language is CXX.  Use the QNX
recommended flag for QCC instead of the gcc compatible -x flag.

Populate new module files to handle system includes and depfiles
when using the QCC compiler.

Remove code which unsets the system include and depfiles related
variables.  When a GNU driver is used instead of the QCC one, the
appropriate flags will be used.  These variables were previously
cleared for lowest-common-denominator compatibility with both
drivers.

3 files changed, 43 insertions, 1 deletions

diff --git a/Source/cmGlobalGenerator.cxx b/Source/cmGlobalGenerator.cxx
index 8a7eee4ebf..03486d8211 100644
--- a/Source/cmGlobalGenerator.cxx
+++ b/Source/cmGlobalGenerator.cxx
@@ -748,7 +748,12 @@ void cmGlobalGenerator::CheckCompilerIdCompatibility(cmMakefile* mf,
 {
   std::string compilerIdVar = "CMAKE_" + lang + "_COMPILER_ID";
   const char* compilerId = mf->GetDefinition(compilerIdVar.c_str());
-  if(compilerId && strcmp(compilerId, "AppleClang") == 0)
+  if(!compilerId)
+    {
+    return;
+    }
+
+  if(strcmp(compilerId, "AppleClang") == 0)
     {
     cmPolicies* policies = this->CMakeInstance->GetPolicies();
     switch(mf->GetPolicyStatus(cmPolicies::CMP0025))
@@ -778,6 +783,37 @@ void cmGlobalGenerator::CheckCompilerIdCompatibility(cmMakefile* mf,
         break;
       }
     }
+
+  if(strcmp(compilerId, "QCC") == 0)
+    {
+    cmPolicies* policies = this->CMakeInstance->GetPolicies();
+    switch(mf->GetPolicyStatus(cmPolicies::CMP0047))
+      {
+      case cmPolicies::WARN:
+        if(!this->CMakeInstance->GetIsInTryCompile())
+          {
+          cmOStringStream w;
+          w << policies->GetPolicyWarning(cmPolicies::CMP0047) << "\n"
+            "Converting " << lang <<
+            " compiler id \"QCC\" to \"GNU\" for compatibility."
+            ;
+          mf->IssueMessage(cmake::AUTHOR_WARNING, w.str());
+          }
+      case cmPolicies::OLD:
+        // OLD behavior is to convert QCC to GNU.
+        mf->AddDefinition(compilerIdVar.c_str(), "GNU");
+        break;
+      case cmPolicies::REQUIRED_IF_USED:
+      case cmPolicies::REQUIRED_ALWAYS:
+        mf->IssueMessage(
+          cmake::FATAL_ERROR,
+          policies->GetRequiredPolicyError(cmPolicies::CMP0047)
+          );
+      case cmPolicies::NEW:
+        // NEW behavior is to keep QCC.
+        break;
+      }
+    }
 }
 
 //----------------------------------------------------------------------------
diff --git a/Source/cmPolicies.cxx b/Source/cmPolicies.cxx
index 020a782a12..a1451f17f1 100644
--- a/Source/cmPolicies.cxx
+++ b/Source/cmPolicies.cxx
@@ -336,6 +336,11 @@ cmPolicies::cmPolicies()
     CMP0046, "CMP0046",
     "Error on non-existent dependency in add_dependencies.",
     3,0,0,0, cmPolicies::WARN);
+
+  this->DefinePolicy(
+    CMP0047, "CMP0047",
+    "Use QCC compiler id for the qcc drivers on QNX.",
+    3,0,0,0, cmPolicies::WARN);
 }
 
 cmPolicies::~cmPolicies()
diff --git a/Source/cmPolicies.h b/Source/cmPolicies.h
index 38f47f1c55..d1bba7bd41 100644
--- a/Source/cmPolicies.h
+++ b/Source/cmPolicies.h
@@ -100,6 +100,7 @@ public:
     CMP0044, ///< Case sensitive <LANG>_COMPILER_ID generator expressions
     CMP0045, ///< Error on non-existent target in get_target_property
     CMP0046, ///< Error on non-existent dependency in add_dependencies
+    CMP0047, ///< Use QCC compiler id for the qcc drivers on QNX.
 
     /** \brief Always the last entry.
      *