https://bugs.gentoo.org/901997
https://github.com/lensfun/lensfun/commit/6e0e92b03f90a264d764f696ba02344ab96b5576
https://github.com/lensfun/lensfun/commit/c54d9bfda1397d3b9deaac1e27d94b0231fdd26a
https://github.com/lensfun/lensfun/commit/011de2e85813ff496a85404b30891352555de077
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,5 +1,5 @@
-# require at least cmake 2.8.12
-CMAKE_MINIMUM_REQUIRED(VERSION 2.8.12 FATAL_ERROR )
+# require at least cmake 3.12
+CMAKE_MINIMUM_REQUIRED(VERSION 3.12 FATAL_ERROR)
 
 # path for helper modules
 set(CMAKE_MODULE_PATH "${CMAKE_MODULE_PATH}" "${CMAKE_SOURCE_DIR}/cmake/modules")
--- a/apps/CMakeLists.txt
+++ b/apps/CMakeLists.txt
@@ -20,27 +20,33 @@ ENDIF(INSTALL_HELPER_SCRIPTS)
 
 
 # Inspired by http://bloerg.net/2012/11/10/cmake-and-distutils.html
+IF(INSTALL_PYTHON_MODULE)
+    FIND_PACKAGE (Python3 COMPONENTS Interpreter REQUIRED)
+    # Windows has a dummy python.exe in the PATH which opens the Microsoft Store, so check if Python is real.
+    EXECUTE_PROCESS(COMMAND ${Python3_EXECUTABLE} --version RESULT_VARIABLE PY_RESULT OUTPUT_QUIET)
+    IF (NOT PY_RESULT EQUAL 0)
+      MESSAGE(FATAL_ERROR "Python3 not found, it might be a dummy python.exe")
+    ENDIF()
 
-FIND_PROGRAM(PYTHON "python3")
-IF(PYTHON)
     SET(SETUP_PY_IN "${CMAKE_CURRENT_SOURCE_DIR}/setup.py.in")
     SET(SETUP_PY    "${CMAKE_CURRENT_BINARY_DIR}/setup.py")
     SET(DEPS_IN     "${CMAKE_CURRENT_SOURCE_DIR}/lensfun/__init__.py.in")
     SET(DEPS        "${CMAKE_CURRENT_BINARY_DIR}/lensfun/__init__.py")
     SET(OUTPUT      "${CMAKE_CURRENT_BINARY_DIR}/build/timestamp")
 
+    FILE(TO_NATIVE_PATH "${CMAKE_CURRENT_BINARY_DIR}" PY_PACKAGE_DIR)
     CONFIGURE_FILE(${SETUP_PY_IN} ${SETUP_PY})
     CONFIGURE_FILE(${DEPS_IN} ${DEPS})
 
     ADD_CUSTOM_COMMAND(OUTPUT ${OUTPUT}
-                       COMMAND ${PYTHON} ${SETUP_PY} build
+                       COMMAND ${Python3_EXECUTABLE} ${SETUP_PY} build
                        COMMAND ${CMAKE_COMMAND} -E touch ${OUTPUT}
-                       DEPENDS ${DEPS_IN})
+                       DEPENDS ${SETUP_PY_IN} ${DEPS_IN})
 
     ADD_CUSTOM_TARGET(python-package ALL DEPENDS ${OUTPUT})
 
     IF(NOT DEFINED SETUP_PY_INSTALL_PREFIX)
       SET(SETUP_PY_INSTALL_PREFIX "${CMAKE_INSTALL_PREFIX}")
     ENDIF()
-    INSTALL(CODE "execute_process(COMMAND ${PYTHON} ${SETUP_PY} install --prefix=\$ENV{DESTDIR}${SETUP_PY_INSTALL_PREFIX})")
-ENDIF(PYTHON)
+    INSTALL(CODE "execute_process(COMMAND ${Python3_EXECUTABLE} ${SETUP_PY} install --prefix=\$ENV{DESTDIR}${SETUP_PY_INSTALL_PREFIX})")
+ENDIF()
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -29,5 +29,5 @@ ADD_EXECUTABLE(test_modifier_coord_geometry test_modifier_coord_geometry.cpp)
 TARGET_LINK_LIBRARIES(test_modifier_coord_geometry lensfun ${COMMON_LIBS})
 ADD_TEST(Modifier_coord_geometry test_modifier_coord_geometry)
 
-FIND_PACKAGE(PythonInterp REQUIRED)
-ADD_TEST(NAME Database_integrity COMMAND ${PYTHON_EXECUTABLE} ${CMAKE_SOURCE_DIR}/tools/check_database/check_database.py ${CMAKE_SOURCE_DIR}/data/db)
+FIND_PACKAGE(Python3 COMPONENTS Interpreter REQUIRED)
+ADD_TEST(NAME Database_integrity COMMAND ${Python3_EXECUTABLE} ${CMAKE_SOURCE_DIR}/tools/check_database/check_database.py ${CMAKE_SOURCE_DIR}/data/db)