testing appveyor eigen include dir pass to cmake

.appveyor.yml

@@ -2,9 +2,6 @@ branches:
   only:
     - master
 
-environment:
-  EIGEN3_INCLUDE_DIR: C:\dev\Eigen3\include\eigen3
-
 install:
   - cmd: if not exist c:\dev\Eigen3\include\eigen3\Eigen\Core (
             curl -L -o eigen-eigen-dc6cfdf9bcec.tar.gz https://bitbucket.org/eigen/eigen/get/3.2.9.tar.gz &&
@@ -28,6 +25,6 @@ build_script:
   # Workaround for CMake not wanting sh.exe on PATH for MinGW
   - rm "C:/Program Files/Git/usr/bin/sh.exe"
   - cmake -E make_directory build
-  - cmake -E chdir build cmake -D ACADOS_WITH_QPOASES=ON -D BLASFEO_TARGET=GENERIC -D HPIPM_TARGET=GENERIC -D BUILD_SHARED_LIBS=OFF -D ACADOS_EXAMPLES=ON -D ACADOS_UNIT_TESTS=ON -G "MinGW Makefiles" ..
+  - cmake -E chdir build cmake -D ACADOS_WITH_QPOASES=ON -D BLASFEO_TARGET=GENERIC -D HPIPM_TARGET=GENERIC -D BUILD_SHARED_LIBS=OFF -D ACADOS_EXAMPLES=ON -D ACADOS_UNIT_TESTS=ON -DEIGEN3_INCLUDE_DIR="C:\dev\Eigen3\include\eigen3" -G "MinGW Makefiles" ..
   - cmake --build build --config Release
   - cmake -E chdir build ctest -V