Add "__GNUC__" macro by default for VSCode

https://github.com/platformio/platformio-vscode-ide/issues/54

platformio/builder/tools/pioide.py

@@ -91,7 +91,9 @@ def DumpIDEData(env):
         "gdb_path":
         util.where_is_program(env.subst("$GDB"), env.subst("${ENV['PATH']}")),
         "prog_path":
-        env.subst("$PROG_PATH")
+        env.subst("$PROG_PATH"),
+        "compiler_type":
+        env.GetCompilerType()
     }
 
     env_ = env.Clone()

platformio/builder/tools/piomisc.py

@@ -199,7 +199,8 @@ def _delete_file(path):
         pass
 
 
-def GetCompilerType(env):
+@util.memoized
+def _get_compiler_type(env):
     try:
         sysenv = environ.copy()
         sysenv['PATH'] = str(env['ENV']['PATH'])
@@ -216,6 +217,10 @@ def GetCompilerType(env):
     return None
 
 
+def GetCompilerType(env):
+    return _get_compiler_type(env)
+
+
 def GetActualLDScript(env):
 
     def _lookup_in_ldpath(script):

platformio/ide/tpls/vscode/.vscode/c_cpp_properties.json.tpl

@@ -30,7 +30,11 @@
 % for define in defines:
                 "{{!define.replace('"', '\\"')}}",
 % end
+% if compiler_type == "gcc":
+                "__GNUC__"
+% else:
                 ""
+% end
             ],
             "intelliSenseMode": "clang-x64"
         }