xapian-core: fix config.cmake for cross compiling

srcpkgs/xapian-core/patches/cross-config.cmake.patch

@@ -0,0 +1,18 @@
+--- cmake/xapian-config.cmake.in	2019-03-02 02:45:31.000000000 +0100
++++ -	2019-05-15 15:59:12.059370469 +0200
+@@ -1,4 +1,14 @@
+-SET(prefix "@prefix@")
++get_filename_component(prefix "${CMAKE_CURRENT_LIST_DIR}/../../../" ABSOLUTE)
++# Use original install prefix when loaded through a "/usr move"
++# cross-prefix symbolic link such as /lib -> /usr/lib.
++get_filename_component(_realCurr "${CMAKE_CURRENT_LIST_DIR}" REALPATH)
++get_filename_component(_realOrig "@prefix@/lib/cmake/xapian" REALPATH)
++if(_realCurr STREQUAL _realOrig)
++  set(prefix "@prefix@")
++endif()
++unset(_realOrig)
++unset(_realCurr)
++
+ SET(exec_prefix "@exec_prefix@")
+ SET(XAPIAN_LIBRARIES "@libdir@/libxapian@LIBRARY_VERSION_SUFFIX@@SHLIBEXT@" CACHE FILEPATH "Libraries for Xapian")
+ SET(XAPIAN_INCLUDE_DIR "@incdir@" CACHE PATH "Include path for Xapian")

srcpkgs/xapian-core/template

@@ -1,7 +1,7 @@
 # Template file for 'xapian-core'
 pkgname=xapian-core
 version=1.4.11
-revision=1
+revision=2
 build_style=gnu-configure
 configure_args="--disable-static"
 makedepends="zlib-devel libuuid-devel"