[evolution] Correct gtkdoc-scan --ignore-headers argument value

[Milan Crha <mcrha src gnome org>]

commit 28386f20f0fe14e449a87f5f586dc89c72ebf802
Author: Milan Crha <mcrha redhat com>
Date:   Tue Nov 8 19:01:29 2016 +0100

    Correct gtkdoc-scan --ignore-headers argument value

 cmake/modules/GtkDoc.cmake |    7 +------
 1 files changed, 1 insertions(+), 6 deletions(-)
---
diff --git a/cmake/modules/GtkDoc.cmake b/cmake/modules/GtkDoc.cmake
index 5640838..3bcca2d 100644
--- a/cmake/modules/GtkDoc.cmake
+++ b/cmake/modules/GtkDoc.cmake
@@ -50,11 +50,6 @@ macro(add_gtkdoc _module _namespace _deprecated_guards _srcdirsvar _depsvar _ign
 
        set(OUTPUT_DOCDIR ${SHARE_INSTALL_PREFIX}/gtk-doc/html/${_module})
 
-       set(_ignore_headers)
-       foreach(_header ${${_ignoreheadersvar}})
-               set(_ignore_headers "${_ignore_headers} ${_header}")
-       endforeach(_header)
-
        set(_filedeps)
        set(_srcdirs)
        foreach(_srcdir ${${_srcdirsvar}})
@@ -72,7 +67,7 @@ macro(add_gtkdoc _module _namespace _deprecated_guards _srcdirsvar _depsvar _ign
                COMMAND ${GTKDOC_SCAN}
                        --module=${_module}
                        --deprecated-guards="${_deprecated_guards}"
-                       --ignore-headers="${_ignore_headers}"
+                       --ignore-headers="${${_ignoreheadersvar}}"
                        --rebuild-sections
                        --rebuild-types
                        ${_srcdirs}