Module cmake/modules/PreventInSourceBuilds.cmake copied from Frida.

This resolves #827.

CMakeLists.txt

@@ -25,8 +25,9 @@ option(BORNAGAIN_CRASHHADLER "Additional machinery to send crash reports" OFF)
 
 #--- Including macros ---
 set(CMAKE_MODULE_PATH ${CMAKE_SOURCE_DIR}/cmake/modules)
+include(PreventInSourceBuilds)
+
 include(BornAgainMacros)
-#AssureOutOfSourceBuilds()
 include(SearchInstalledSoftware)
 include(CheckCompiler)
 include(BornAgainConfiguration)

cmake/modules/PreventInSourceBuilds.cmake

+# 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("We do not allow cmake to be run in the source directory.")
+    message("You must run cmake in a build directory.")
+    message("For example:")
+    message("  cd <source directory>")
+    message("  mkdir build")
+    message("  cd build")
+    message("  cmake .. # or ccmake, or cmake-gui")
+    message("")
+    message("To clean up after this aborted in-place compilation:")
+    message("  rm -r CMakeCache.txt CMakeFiles/")
+    message("###########################################################################")
+    message(FATAL_ERROR "Quitting configuration")
+  endif()
+endfunction()
+
+AssureOutOfSourceBuilds()