Add graph references

references/igraph-1.0.1/etc/cmake/PreventInSourceBuilds.cmake

@@ -0,0 +1,34 @@
+# Original source of this script:
+# https://raw.githubusercontent.com/InsightSoftwareConsortium/ITK/master/CMake/PreventInSourceBuilds.cmake
+#
+# Thanks to the ITK project!
+#
+# This function will prevent in-source builds
+function(AssureOutOfSourceBuilds)
+  # make sure the user doesn't play dirty with symlinks
+  get_filename_component(srcdir "${CMAKE_SOURCE_DIR}" REALPATH)
+  get_filename_component(bindir "${CMAKE_BINARY_DIR}" REALPATH)
+
+  # disallow in-source builds
+  if("${srcdir}" STREQUAL "${bindir}")
+    message("##########################################################################")
+    message("# igraph should not be configured & built in the igraph source directory")
+    message("# You must run cmake in a build directory.")
+    message("#")
+    message("# Example:")
+    message("# mkdir build; cd build; cmake ..; make")
+    message("#")
+    message("# NOTE: Given that you already tried to make an in-source build")
+    message("#       CMake have already created several files & directories")
+    message("#       in your source tree. If you are using git, run 'git clean -dfx'")
+    message("#       to start from scratch. If you don't have git, remove")
+    message("#       CMakeCache.txt and the CMakeFiles/ folder from the top of")
+    message("#       the source tree.")
+    message("#")
+    message("##########################################################################")
+    message("")
+    message(FATAL_ERROR "Quitting configuration")
+  endif()
+endfunction()
+
+AssureOutOfSourceBuilds()