Use vcpkg's libraries for pangolin dependencies

Also fixes missing header that doesn't get installed

ports/pangolin/CONTROL

@@ -1,4 +1,4 @@
 Source: pangolin
 Version: 0.5-1
-Build-Depends: eigen3
+Build-Depends: eigen3, glew, libpng, libjpeg-turbo, ffmpeg
 Description: Lightweight GUI Library

ports/pangolin/portfile.cmake

@@ -13,6 +13,9 @@ vcpkg_configure_cmake(
     PREFER_NINJA
     OPTIONS
         -DCMAKE_WINDOWS_EXPORT_ALL_SYMBOLS=ON
+        -DBUILD_EXTERN_GLEW=OFF
+        -DBUILD_EXTERN_LIBPNG=OFF
+        -DBUILD_EXTERN_LIBJPEG=OFF
 )
 
 vcpkg_install_cmake()
@@ -39,6 +42,9 @@ file(WRITE ${CURRENT_PACKAGES_DIR}/share/pangolin/PangolinTargets-release.cmake
 
 file(REMOVE_RECURSE ${CURRENT_PACKAGES_DIR}/debug/include)
 
+# Copy missing header file
+file(COPY ${CURRENT_BUILDTREES_DIR}/${TARGET_TRIPLET}-dbg/src/include/pangolin/pangolin_export.h DESTINATION ${CURRENT_PACKAGES_DIR}/include/pangolin)
+
 # Put the license file where vcpkg expects it
 file(COPY ${SOURCE_PATH}/LICENCE DESTINATION ${CURRENT_PACKAGES_DIR}/share/Pangolin/)
 file(RENAME ${CURRENT_PACKAGES_DIR}/share/Pangolin/LICENCE ${CURRENT_PACKAGES_DIR}/share/Pangolin/copyright)