[angle] Fix mingw build

[dg0yt]

• What does your PR fix?

  • Fixes dulicate "lib" in name of import libs for libEGL and libGLESv2.
  • Fixes building with mingw.

• Which triplets are supported/not supported? Have you updated the CI baseline?

  no change, no.

• Does your PR follow the maintainer guide?

  yes

• If you have added/updated a port: Have you run ./vcpkg x-add-version --all and committed the result?

  yes

---

Disclaimer: not tested with actual app, just another step towards building Qt.

[dg0yt]

qt5-base doesn't use angle on windows?!

[ras0219]

Shouldn't libANGLE be given a similar IMPORT_PREFIX ""?

[dg0yt]

libANGLE is STATIC so there is no import library:

vcpkg/ports/angle/CMakeLists.txt

Line 537 in a863c84

add_library(libANGLE STATIC ${LIBANGLE_SOURCES})

[dg0yt]

qt5-base doesn't use angle on windows?!

@ras0219 Do you have an idea why it is not supported for windows?

vcpkg/ports/qt5-base/vcpkg.json

Lines 7 to 11 in a863c84

	"dependencies": [
	{
	"name": "angle",
	"platform": "!windows"
	},

[Neumann-A]

@ras0219 Do you have an idea why it is not supported for windows?

on windows the default is always to use -opengl dynamic even for static builds so angle is not required for windows. (see https://doc.qt.io/qt-5/windows-requirements.html.)
angle also has been completely removed from Qt6. It is a completely optional runtime dependency which nowadays can commonly be replaced by the normal windows opengl driver. Alternatively software rendering via mesa would also be possible.