[gobject-introspection] Generate relative paths for gio-unix C header includes

[Mikhail Zabaluev <mzabaluev src gnome org>]

commit cb956f565785835a6621ca8b89634fe58f59feaf
Author: Mikhail Zabaluev <mikhail zabaluev gmail com>
Date:   Sun Oct 18 13:23:20 2015 +0300

    Generate relative paths for gio-unix C header includes
    
    In the generated GIR for Gio-2.0, the <c:include/> elements for
    gio-unix headers got emitted with absolute pathnames. Obviously, this
    does not work well when GIR needs to be checked into repositories,
    is used to build in other locations, etc.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=756679

 Makefile-gir.am |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/Makefile-gir.am b/Makefile-gir.am
index 9aca664..a09260a 100644
--- a/Makefile-gir.am
+++ b/Makefile-gir.am
@@ -152,13 +152,15 @@ GIO_LIBDIR=$(shell "${PKG_CONFIG}" --variable=libdir gio-2.0)
 GIO_LIBRARY=gio-2.0
 
 if HAVE_GIO_UNIX
-GIO_UNIX_HDRS=$(shell "${PKG_CONFIG}" --variable=includedir gio-unix-2.0)/gio-unix-2.0/gio/*.h
+GIO_UNIX_INCLUDEDIR = $(shell "${PKG_CONFIG}" --variable=includedir gio-unix-2.0)/gio-unix-2.0
+GIO_UNIX_HDRS = $(GIO_UNIX_INCLUDEDIR)/gio/*.h
 GIO_UNIX_PACKAGES = gio-unix-2.0
 else
+GIO_UNIX_INCLUDEDIR =
 GIO_UNIX_HDRS=
 GIO_UNIX_PACKAGES =
 endif
-GIO_CINCLUDES=$(patsubst %,--c-include='%',$(shell echo $(GIO_UNIX_HDRS)))
+GIO_CINCLUDES=$(patsubst $(GIO_UNIX_INCLUDEDIR)/%,--c-include='%',$(wildcard $(GIO_UNIX_HDRS)))
 
 Gio-2.0.gir: GObject-2.0.gir