Added header moduoe to documentation

CMakeLists.txt

@@ -37,7 +37,7 @@ option(IF97_HEADER_MODULE "Install header file only" OFF)
 option(IF97_CMAKE_MODULE "Install CMake interface library" OFF)
 option(IF97_FLAG "Skip IF97 test executable" OFF)
 
-list(APPEND options ${IF97_PRIME_MODULE} ${IF97_MATHCAD15_MODULE} ${IF97_CMAKE_MODULE} ${IF97_FLAG})
+list(APPEND options ${IF97_PRIME_MODULE} ${IF97_MATHCAD15_MODULE} ${IF97_HEADER_MODULE} ${IF97_CMAKE_MODULE} ${IF97_FLAG})
 set(options_count 0)
 foreach(option_value ${options})
   if(option_value)

README.md

@@ -34,13 +34,15 @@ This will spit out the values for the computer-program verification, they should
 Accessing IF97 from your software
 ---------------------------------
 
+The simplest way to include IF97 in your project is o simply copy the header file. If you are looking for an installation command, you can use `cmake .. -DIF97_HEADER_MODULE=ON; cmake --build . --target install`.
+
 There is a `wrapper` directory for 3rd party applications, including:
 - [Mathcad 15](wrapper/Mathcad) (Jeff Henning main contributor)
 - [Mathcad Prime](wrapper/Mathcad) (Jeff Henning main contributor)
 
 See the README in each wrapper directory for instructions on building and installing each.
 
-Furthermore, there is an interface library target that installs the header file. This target can also be digested by other CMake-based projects using the `add_subdirectory` command. Enable it with the CMake option `cmake .. -DIF97_CMAKE_MODULE=ON`.
+Furthermore, there is an interface library target that installs the header file. This target can also be digested by other CMake-based projects using the `add_subdirectory` command. Enable it with the CMake option `cmake .. -DIF97_CMAKE_MODULE=ON; cmake --build . --target install`.
 
 
 Compiler Switches