Merge branch 'adjust-cmake-to-xdiff-and-reftable-merge-into-libgit'

When the Rust preparations merged libxdiff and libreftable into libgit,
the CMake definition was left untouched. Here are the corresponding
changes.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

contrib/buildsystems/CMakeLists.txt

@@ -705,18 +705,6 @@ list(APPEND libgit_SOURCES "${CMAKE_BINARY_DIR}/version-def.h")
 
 add_library(libgit ${libgit_SOURCES} ${compat_SOURCES})
 
-#libxdiff
-parse_makefile_for_sources(libxdiff_SOURCES ${CMAKE_SOURCE_DIR}/Makefile "XDIFF_OBJS")
-
-list(TRANSFORM libxdiff_SOURCES PREPEND "${CMAKE_SOURCE_DIR}/")
-add_library(xdiff STATIC ${libxdiff_SOURCES})
-
-#reftable
-parse_makefile_for_sources(reftable_SOURCES ${CMAKE_SOURCE_DIR}/Makefile "REFTABLE_OBJS")
-
-list(TRANSFORM reftable_SOURCES PREPEND "${CMAKE_SOURCE_DIR}/")
-add_library(reftable STATIC ${reftable_SOURCES})
-
 if(WIN32)
 	add_custom_command(OUTPUT ${CMAKE_BINARY_DIR}/git.rc
 			COMMAND "${SH_EXE}" "${CMAKE_SOURCE_DIR}/GIT-VERSION-GEN"
@@ -746,7 +734,7 @@ endif()
 #link all required libraries to common-main
 add_library(common-main OBJECT ${CMAKE_SOURCE_DIR}/common-main.c)
 
-target_link_libraries(common-main libgit xdiff reftable ${ZLIB_LIBRARIES})
+target_link_libraries(common-main libgit ${ZLIB_LIBRARIES})
 if(Intl_FOUND)
 	target_link_libraries(common-main ${Intl_LIBRARIES})
 endif()