diff --git a/scripts/common.cmake b/scripts/common.cmake
index b7fd72c..2216e09 100644
--- a/scripts/common.cmake
+++ b/scripts/common.cmake
@@ -142,3 +142,32 @@
     add_compiler_flags(/WX)
     add_compiler_flags(/W4) # /Wall is too aggressive - even the standard C headers give thousands of errors...
 endif()
+
+# add a custom target that assembles the single header when any of the parts are touched
+
+set(cat_cmd "cat")
+set(doctest_include_folder "${CURRENT_LIST_DIR_CACHED}/../doctest/")
+set(doctest_parts_folder "${CURRENT_LIST_DIR_CACHED}/../doctest/parts/")
+if(WIN32)
+    set(cat_cmd "type")
+    STRING(REGEX REPLACE "/" "\\\\" doctest_include_folder ${doctest_include_folder})
+    STRING(REGEX REPLACE "/" "\\\\" doctest_parts_folder ${doctest_parts_folder})
+endif()
+
+add_custom_command(
+    OUTPUT ${doctest_include_folder}doctest.h
+    DEPENDS
+        ${doctest_parts_folder}doctest_fwd.h
+        ${doctest_parts_folder}doctest_impl.h
+    COMMAND echo // ======================================================================  > ${doctest_include_folder}doctest.h
+    COMMAND echo // == DO NOT MODIFY THIS FILE BY HAND - IT IS AUTO GENERATED BY CMAKE! == >> ${doctest_include_folder}doctest.h
+    COMMAND echo // ====================================================================== >> ${doctest_include_folder}doctest.h
+    COMMAND
+        ${cat_cmd}
+        ${doctest_parts_folder}doctest_fwd.h
+        ${doctest_parts_folder}doctest_impl.h
+        >>
+        ${doctest_include_folder}doctest.h
+    COMMENT "assembling the single header")
+
+add_custom_target(assemble_single_header ALL DEPENDS ${doctest_include_folder}doctest.h)