Rename c++1z to c++17 in the configure api

It is 2019, so the name c++17 is more than fixed by now.

At the same time remove an old restriction on using -c++std= with MSVC,
since VS2017 (15.7), we have been able to request c++14 and c++17.

Change-Id: I7129799a2e46301b7ec1322251a3805f4d6b20a8
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

config_help.txt

@@ -139,8 +139,8 @@ Build options:
   -coverage {trace-pc-guard}
                          Add code coverage instrumentation (Clang only)
 
-  -c++std <edition> .... Select C++ standard <edition> [c++1z/c++14/c++11]
-                         (Not supported with MSVC)
+  -c++std <edition> .... Select C++ standard <edition> [c++17/c++14/c++11]
+                         (Not supported with MSVC 2015)
 
   -sse2 ................ Use SSE2 instructions [auto]
   -sse3/-ssse3/-sse4.1/-sse4.2/-avx/-avx2/-avx512

configure.json

@@ -319,7 +319,7 @@
             }
         },
         "c++1z": {
-            "label": "C++1z support",
+            "label": "C++17 support",
             "type": "compile",
             "test": {
                 "head": [
@@ -907,7 +907,7 @@
             "output": [ "publicFeature", "publicQtConfig" ]
         },
         "c++1z": {
-            "label": "C++1z",
+            "label": "C++17",
             "condition": "features.c++14 && tests.c++1z",
             "output": [ "publicFeature", "publicQtConfig" ]
         },

configure.pri

@@ -14,9 +14,6 @@ defineTest(qtConfCommandline_qmakeArgs) {
 }
 
 defineTest(qtConfCommandline_cxxstd) {
-    msvc: \
-        qtConfAddError("Command line option -c++std is not supported with MSVC compilers.")
-
     arg = $${1}
     val = $${2}
     isEmpty(val): val = $$qtConfGetNextCommandlineArg()
@@ -26,7 +23,7 @@ defineTest(qtConfCommandline_cxxstd) {
         } else: contains(val, "(c\+\+)?(14|1y)") {
             qtConfCommandlineSetInput("c++14", "yes")
             qtConfCommandlineSetInput("c++1z", "no")
-        } else: contains(val, "(c\+\+)?(1z)") {
+        } else: contains(val, "(c\+\+)?(17|1z)") {
             qtConfCommandlineSetInput("c++14", "yes")
             qtConfCommandlineSetInput("c++1z", "yes")
         } else {