µVision export: Add ARMC6 -std handling

This is limited to ARMC6 because as of µVision V5.27 you can't set C++11
for ARMC5.

Also, selection of gnu++14, which we want to use, can't be done
explicitly, as it's not in µVision's list. But it is the default for ARM
Compiler 6.11 and 6.12, so we can get it implicitly.

tools/export/uvision/__init__.py

@@ -288,6 +288,34 @@ def generate(self):
         ctx['fputype'] = self.format_fpu(ctx['device'].core)
         ctx['armc6'] = int(self.TOOLCHAIN is 'ARMC6')
         ctx['toolchain_name'] = self.TOOLCHAIN_NAME
+
+        std = [flag for flag in self.flags['c_flags'] if flag.startswith("-std=")]
+        if len(std) >= 1:
+            std = std[-1][len('-std='):]
+        else:
+            std = None
+        c_std = {
+            'c89': 1, 'gnu89': 2,
+            'c90': 1, 'gnu90': 2,
+            'c99': 3, 'gnu99': 4,
+            'c11': 5, 'gnu11': 6,
+        }
+        ctx['v6_lang'] = c_std.get(std, 0)
+
+        std = [flag for flag in self.flags['cxx_flags'] if flag.startswith("-std=")]
+        if len(std) >= 1:
+            std = std[-1][len('-std='):]
+        else:
+            std = None
+        cpp_std = {
+            'c++98': 1, 'gnu++98': 2,
+            'c++03': 5, 'gnu++03': 2, # UVision 5.27.1.0 does not support gnu++03 - fall back to gnu++98
+            'c++11': 3, 'gnu++11': 4,
+            'c++14': 6, 'gnu++14': 0, # UVision 5.27.1.0 can't manually select gnu++14, but it is the default!
+            'c++17': 6, 'gnu++17': 0, # UVision 5.27.1.0 does not support c++17/gnu++17 - fall back to c++14/gnu++14
+        }
+        ctx['v6_lang_p'] = cpp_std.get(std, 0)
+
         ctx.update(self.format_flags())
         self.gen_file(
             'uvision/uvision.tmpl', ctx, self.project_name + ".uvprojx"

tools/export/uvision/uvision.tmpl

@@ -369,8 +369,8 @@
             <uSurpInc>0</uSurpInc>
             <uC99>1</uC99>
             <useXO>0</useXO>
-            <v6Lang>4</v6Lang>
-            <v6LangP>2</v6LangP>
+            <v6Lang>{{v6_lang}}</v6Lang>
+            <v6LangP>{{v6_lang_p}}</v6LangP>
             <vShortEn>1</vShortEn>
             <vShortWch>1</vShortWch>
             <v6Lto>0</v6Lto>