Fix rlottie options not taking effect (CMP0077)

With cmake_minimum_required(3.10), policy CMP0077 is OLD: option()
in the rlottie submodule discards normal variables set before
add_subdirectory and resets them to their defaults (ON). This left
LOTTIE_MODULE=ON, excluding stb_image.cpp from the build and causing
undefined references to lottie_image_load/lottie_image_free/
lottie_image_load_from_data at link time.

Set the options as cache variables with FORCE instead; option()
never overrides an existing cache entry.

Author: Kartatz

TMessagesProj/jni/CMakeLists.txt

@@ -80,10 +80,13 @@ target_link_libraries(tgnet
 
 #rlottie
 set(BUILD_SHARED_LIBS OFF)
-set(LOTTIE_MODULE OFF)
-set(LOTTIE_THREAD OFF)
-set(LOTTIE_CACHE OFF)
-set(LOTTIE_TEST OFF)
+# NOTE: must be CACHE ... FORCE because this project requires CMake 3.10,
+# so CMP0077 is OLD and option() in the submodule would discard plain
+# normal variables and reset them to their defaults (ON).
+set(LOTTIE_MODULE OFF CACHE BOOL "" FORCE)
+set(LOTTIE_THREAD OFF CACHE BOOL "" FORCE)
+set(LOTTIE_CACHE OFF CACHE BOOL "" FORCE)
+set(LOTTIE_TEST OFF CACHE BOOL "" FORCE)
 add_subdirectory(rlottie)
 target_compile_options(rlottie PUBLIC
         -Wall -fno-rtti -finline-functions -ffast-math -Oz -fno-unwind-tables -fno-asynchronous-unwind-tables -Wnon-virtual-dtor -Woverloaded-virtual -Wno-unused-parameter -fvisibility=hidden)