Allow external control of whether to install

Author: scribam

CMakeLists.txt

@@ -12,7 +12,8 @@ if (CMAKE_VERSION VERSION_LESS "3.21")
     string(COMPARE EQUAL ${CMAKE_CURRENT_SOURCE_DIR} ${CMAKE_SOURCE_DIR} PROJECT_IS_TOP_LEVEL)
 endif()
 
-if (PROJECT_IS_TOP_LEVEL)
+option(VMA_ENABLE_INSTALL "Install VulkanMemoryAllocator" ${PROJECT_IS_TOP_LEVEL})
+if (VMA_ENABLE_INSTALL)
     include(GNUInstallDirs)
     include(CMakePackageConfigHelpers)