MSYS2 MinGW package

Hello, I am the maintainer of glbinding [package](https://github.com/Alexpux/MINGW-packages/tree/master/mingw-w64-glbinding) in MSYS2. After updating this package to 2.0.0 I have found that I can no longer build and install both static and shared libraries side by side.
Problem is in `glbinding-export.cmake`:

```
...
# Create imported target glbinding::glbinding
add_library(glbinding::glbinding SHARED IMPORTED) # This should be UNKNOWN
...
```

[Current package](https://github.com/Alexpux/MINGW-packages/blob/master/mingw-w64-glbinding/PKGBUILD) installs just shared libraries. I am making a split package now.
MSYS2 uses pacman, so here is my `PKGBUILD`:

```
# Maintainer: Nazar Mishturak

_realname=glbinding
pkgbase="mingw-w64-${_realname}"
pkgname=("${MINGW_PACKAGE_PREFIX}-${_realname}"
"${MINGW_PACKAGE_PREFIX}-${_realname}-static"
)
pkgver=2.0.0
pkgrel=2
arch=('any')
url='https://github.com/cginternals/glbinding'
pkgdesc="A C++ binding for the OpenGL API, generated using the gl.xml specification (mingw-w64)"
depends=("${MINGW_PACKAGE_PREFIX}-gcc-libs"
"${MINGW_PACKAGE_PREFIX}-glfw") # Required for tools
makedepends=("${MINGW_PACKAGE_PREFIX}-gcc"
"${MINGW_PACKAGE_PREFIX}-cmake"
"${MINGW_PACKAGE_PREFIX}-doxygen")
license=('MIT')
# Is this needed? If yes how to make it work? Pacman detects file conflict anyway
#conflicts_mingw-w64-x86_64-glbinding=("${MINGW_PACKAGE_PREFIX}-${_realname}-static")
#conflicts_mingw-w64-i686-glbinding=("${MINGW_PACKAGE_PREFIX}-${_realname}-static")
#conflicts_mingw-w64-x86_64-glbinding-static=("${MINGW_PACKAGE_PREFIX}-${_realname}")
#conflicts_mingw-w64-i686-glbinding-static=("${MINGW_PACKAGE_PREFIX}-${_realname}")
options=('strip' 'staticlibs' 'docs')

source=(${_realname}-${pkgver}.tar.gz::"https://github.com/cginternals/glbinding/archive/v${pkgver}.tar.gz"
'mingw-unix-layout.patch'
'config-export-location.patch')
sha256sums=('105d8c2d6e345ccd2b49a1aaf3ce1d5fb2845d89c21c6ed3b655d42611b78662'
'4d3960a529d6b76e5d63afbaab1376b687f8cc8899e3d5f10a17b3a18cf29ef5'
'76bee25b5647806a397ef1ec0104851031b4a392aec9c97bb99380efe3051e6a')

prepare() {
cd "${srcdir}/${_realname}-${pkgver}"
# sed -i 's/$/\r/' "${srcdir}/mingw-unix-layout.patch"
patch -p1 -i "${srcdir}/mingw-unix-layout.patch"
patch -p1 -i "${srcdir}/config-export-location.patch"
}

build() {
cd "${srcdir}/${_realname}-${pkgver}"

local BUILD_TYPE="Release"
if check_option "debug" "y"; then
BUILD_TYPE="Debug"
fi

# Build shared libs
[[ -d ${srcdir}/shared-${MINGW_CHOST} ]] && rm -rf ${srcdir}/shared-${MINGW_CHOST}
mkdir -p ${srcdir}/shared-${MINGW_CHOST}
cd ${srcdir}/shared-${MINGW_CHOST}

MSYS2_ARG_CONV_EXCL="-DCMAKE_INSTALL_PREFIX=" \
${MINGW_PREFIX}/bin/cmake \
-G"MSYS Makefiles" \
-DCMAKE_BUILD_TYPE=${BUILD_TYPE} \
-DCMAKE_INSTALL_PREFIX=${MINGW_PREFIX} \
-DCMAKE_C_COMPILER=${MINGW_CHOST}-gcc \
-DCMAKE_CXX_COMPILER=${MINGW_CHOST}-g++ \
-DOPTION_BUILD_EXAMPLES=OFF \
-DOPTION_BUILD_TESTS=OFF \
-DBUILD_SHARED_LIBS=ON \
-DOPTION_BUILD_DOCS=ON \
../${_realname}-${pkgver}
make

# Build static libs
[[ -d ${srcdir}/static-${MINGW_CHOST} ]] && rm -rf ${srcdir}/static-${MINGW_CHOST}
mkdir -p ${srcdir}/static-${MINGW_CHOST}
cd ${srcdir}/static-${MINGW_CHOST}

MSYS2_ARG_CONV_EXCL="-DCMAKE_INSTALL_PREFIX=" \
${MINGW_PREFIX}/bin/cmake \
-G"MSYS Makefiles" \
-DCMAKE_BUILD_TYPE=${BUILD_TYPE} \
-DCMAKE_INSTALL_PREFIX=${MINGW_PREFIX} \
-DCMAKE_C_COMPILER=${MINGW_CHOST}-gcc \
-DCMAKE_CXX_COMPILER=${MINGW_CHOST}-g++ \
-DOPTION_BUILD_EXAMPLES=OFF \
-DOPTION_BUILD_TESTS=OFF \
-DBUILD_SHARED_LIBS=OFF \
-DOPTION_BUILD_DOCS=ON \
../${_realname}-${pkgver}
make
}

package_shared() {
cd "${srcdir}/shared-${MINGW_CHOST}"
make DESTDIR=${pkgdir} install
}

package_static() {
cd "${srcdir}/static-${MINGW_CHOST}"
make DESTDIR=${pkgdir} install
}

package_mingw-w64-x86_64-glbinding() {
package_shared
}
package_mingw-w64-i686-glbinding() {
package_shared
}

package_mingw-w64-x86_64-glbinding-static() {
package_static
}
package_mingw-w64-i686-glbinding-static() {
package_static
}
```

Any workaround possible? Or I should use split packaging?