diff -rupN gmsh-4.2.1-source/CMakeLists.txt gmsh-4.2.1-source-new/CMakeLists.txt
--- gmsh-4.2.1-source/CMakeLists.txt	2019-03-07 21:27:56.030262376 +0100
+++ gmsh-4.2.1-source-new/CMakeLists.txt	2019-03-07 21:27:56.033262096 +0100
@@ -1834,7 +1834,7 @@ endif()
 if(ENABLE_BUILD_SHARED OR ENABLE_BUILD_DYNAMIC)
   install(TARGETS shared DESTINATION ${GMSH_LIB} OPTIONAL)
   # FIXME once we cleanup the installation of the python module
-  install(TARGETS shared DESTINATION ${CMAKE_CURRENT_SOURCE_DIR}/api OPTIONAL)
+  # install(TARGETS shared DESTINATION ${CMAKE_CURRENT_SOURCE_DIR}/api OPTIONAL)
 endif()
 
 if(ENABLE_ONELAB)