Source incorrectly referenced when using relative path

Hi,

I generate XCode projects from an autotool project, using it to build and using XCode to package everything.

I have the following snippet in my configure.ac

AS_IF([ test "${SYS}" = "darwin" ],[
  AC_ARG_VAR([XCODEGEN],[xcode project generator])
  AC_PATH_PROG([XCODEGEN],[xcodegen],[no])
  AS_IF([ test "x${XCODEGEN}" != "xno" ], [
    VLC_BUILD_DIR="." VLC_SRC_DIR="${srcdir}" VLC_PLATFORM=tvOS \
    ${XCODEGEN} generate --project . --spec "${srcdir}/extras/package/apple/xcodegen.yml" --project-root .
  ])
])

Which, to be more readable, expands to

VLC_SRC_DIR=../.. VLC_PLATFORM="tvOS" VLC_BUILD_DIR=.  xcodegen generate --project . --spec ../../extras/package/apple/xcodegen.yml --project-root .

Unfortunately, xcodegen detects the files in the source directory, so raise no issues, and generate the references, but the generated xcode project uses the include directory in the build directory, discarding the ../../ relative path prefix.

To ensure this is not coming from my configuration, here is my spec file:

name: VLC
options:
  bundleIdPrefix: org.videolan.vlc
  deploymentTarget:
    iOS: 9.0
targets:
  VLCAutomake:
    type: ""
    platform: ${VLC_PLATFORM}
    legacy:
      toolPath: /usr/bin/make
      passSettings: true
      attributes: $(ACTIONS)
      workingDirectory: ${VLC_BUILD_DIR}
    sources:
      - path: "${VLC_SRC_DIR}/src"
        excludes: "**/Makefile.in"
      - path: "${VLC_SRC_DIR}/include"
        excludes: "**/Makefile.in"
      - path: "${VLC_SRC_DIR}/modules"
        excludes: "**/Makefile.in"
  vlccoreios:
    type: "application"
    platform: ${VLC_PLATFORM}
    dependencies:
      - target: VLCAutomake
    info:
      path: "vlccoreios/Info.plist"
    sources:
      - path: ${VLC_BUILD_DIR}/test/vlccoreios
        type: file
        optional: true
        buildPhase:
          copyFiles:
            destination: executables

But since I needed optional: true for the vlccoreios path, it seems to me that the generation probably has an issue with relative path here.

Reproduce the issue with the configure.ac snippet, the extras/package/apple/xcodegen.yml spec, and the relative paths shown in the xcodegen generate command. Inspect how the generator resolves the sources and the optional vlccoreios path. Done means the generated Xcode project preserves the ../../ prefix and correctly references source and build directories.