Use CMake to find the Python interpreter to use when running scripts

This makes it easier to control which interpreter is used, rather than
always using python3 from PATH.

Author: bdash

CMakeLists.txt

@@ -9,6 +9,8 @@ option(BN_ALLOW_STUBS "Allow generating and linking against stubs if a Binary Ni
 option(BN_REF_COUNT_DEBUG "Add extra debugging checks for RefCountObject leaks" OFF)
 mark_as_advanced(BN_REF_COUNT_DEBUG)
 
+find_package(Python3 3.10 COMPONENTS Interpreter REQUIRED)
+
 if(NOT CMAKE_SIZEOF_VOID_P EQUAL 8)
     if (MSVC)
         message(FATAL_ERROR "Binary Ninja is 64-bit only (try -G \"${CMAKE_GENERATOR} Win64\")")

arch/x86/CMakeLists.txt

@@ -2,17 +2,19 @@ cmake_minimum_required(VERSION 3.15 FATAL_ERROR)
 
 project(arch_x86)
 
+find_package(Python3 COMPONENTS Interpreter REQUIRED)
+
 OPTION(BUILD_SHARED_LIBS "Build shared libraries" OFF)
 OPTION(YASM_BUILD_TESTS "Enable building of tests" OFF)
 add_subdirectory(yasm)
 
 set(XED_CONFIGURE_ARGS --no-encoder just-gen)
 if(WIN32)
 	execute_process(COMMAND ${CMAKE_COMMAND} -E env OS=Windows_NT PYTHONPATH=${PROJECT_SOURCE_DIR}/mbuild
-		py -3 ${PROJECT_SOURCE_DIR}/xed/mfile.py ${XED_CONFIGURE_ARGS}
+		${Python3_EXECUTABLE} ${PROJECT_SOURCE_DIR}/xed/mfile.py ${XED_CONFIGURE_ARGS}
 		WORKING_DIRECTORY ${PROJECT_BINARY_DIR})
 else()
-	execute_process(COMMAND python3 ${PROJECT_SOURCE_DIR}/xed/mfile.py ${XED_CONFIGURE_ARGS}
+	execute_process(COMMAND ${Python3_EXECUTABLE} ${PROJECT_SOURCE_DIR}/xed/mfile.py ${XED_CONFIGURE_ARGS}
 		WORKING_DIRECTORY ${PROJECT_BINARY_DIR})
 endif()