The code below compiled and works fine under Arduino IDE and platformio, so I guess that something wrong is in the visualmicro. If I change board type to ArduinoYun, compilation passes OK but downloading destroys board bootloader.

#define BLYNK_PRINT Serial
#define BLYNK_DEBUG

#include <BlynkSimpleYun.h>

char auth[] = "65dc98d70cd2419982e7f47b3cf";
// we need no ssid and password because Linkit connected wifi itself
char a;
int LED = 13 ;

void setup() {
  Serial.begin(115200);
  delay(2000);
  Blynk.begin(auth);
  Serial.println("Blynk.begin");
  pinMode(LED, OUTPUT);
  digitalWrite(LED, LOW);
}

void loop() {

  Blynk.run();

}

 

As could bee seen from the attached log, compiler refers to wrong core folder Digilent. I see no resonable explanation to that. 

Also, IDE periodically lost include references, marking red #include <BlynkSimpleYun.h>

Interesting. Please explain how to install your hardware thanks.

Damn I pulled to install support  for Digilent boards.
Now after deinstall and reinstall VisualMicro, and deleting Arduino15 folder every lauch VM creates a set of folders:
.43\pic32mx\include\
and  installs there every new package, e.g. esp8266. Naturally compilation does not work.
Nothing helps to solve it. I searched registry, all related folders and files, but could not figure out where VM stores references to Digilent.
How it could be solved?

I did so. VM does not see hardware esp8266 installed by Arduino  IDE.

The build problem is because the hardware incorrectly defines the usb info for the compiler. PlatformIO have their own hardware so won't be affected and I suspect that a change in the arduino ide "fixes" the issue which I will look at doing for the next release of visual micro.

You can solve the issue by adding a board.txt to the project (use the "add code" menu for a shortcut to create board.txt) and then adding this line to it:-

build.usb_flags=-DUSB_VID={build.vid} -DUSB_PID={build.pid} '-DUSB_MANUFACTURER={build.usb_manufacturer}' '-DUSB_PRODUCT={build.usb_product}' 

More info ...

Note that we use single quotes around the -D define, because {build.usb_manufacturer} and {build.usb_product} are defined strings that themselves have "double quotes". 

Therefore, the incorrect result for the compiler is as folllows:-

 "-DUSB_MANUFACTURER="board usb name"" 

You would see these doubled double quotes in the verbose compiler output in visual micro and in the arduino ide. The board.txt override changes the outer double quotes to single quotes which is how the arduino boards are defined and that works. This is related to how windows runs exe command line processes which is what we do when we compile. The inner double quotes of each -D define should either be escaped  -Dfoo=\"my String\" or the entire -D surrounded with single quotes instead of double quotes as in the fix above.

as concerns the 8266 hardware not showing in visual micro please open a new thread and report which esp8266 hardware and version + .json file you used to install in the arduino ide. It's possible if you have removed the .json from the arduino ide after installing esp8266 then visual micro will no longer list the hardware but please continue this in another thread