ifcopenshell installation notion about compiling only specific schemas

cmake/CMakeLists.txt

@@ -756,6 +756,8 @@ if(NOT SCHEMA_VERSIONS)
     endif()
 endif()
 
+message(STATUS "IFC SCHEMA_VERSIONS that will be used for the build: ${SCHEMA_VERSIONS}.")
+
 foreach(schema ${SCHEMA_VERSIONS})
     add_definitions(-DHAS_SCHEMA_${schema})
 endforeach()

src/ifcopenshell-python/docs/ifcopenshell/installation.rst

@@ -10,6 +10,9 @@ you how to compile and install IfcOpenShell.
     IfcOpenShell-Python, IfcConvert, or the other utilities such as IfcClash or
     IfcDiff. Compilation is only necessary for C++ developers.
 
+    By default, it will compile all available IFC schemas. To reduce compilation time you can specify
+    only the schemas you need in `CMakeLists.txt` with `set(SCHEMA_VERSIONS "2x3" "4")`.
+
 You will need:
 
 - `Git <https://git-scm.com/>`__