- Honor CFLAGS and DEBUG
- Use system libpng on arm platforms
- Allow disabling Wayland even if found

Index: CMakeLists.txt
--- CMakeLists.txt.orig
+++ CMakeLists.txt
@@ -188,10 +188,9 @@ if(UNIX AND NOT (APPLE OR ANDROID) AND VULKAN)
 	find_package(Wayland)
 	if(NOT WAYLAND_FOUND)
 		message(STATUS "Could not find Wayland libraries, disabling Wayland WSI support for Vulkan.")
-	else()
+	elseif(USE_WAYLAND_WSI)
 		include_directories(${WAYLAND_INCLUDE_DIR})
 		add_definitions(-DVK_USE_PLATFORM_WAYLAND_KHR)
-		add_definitions(-DUSE_WAYLAND_WSI=ON)
 	endif()
 
 	if(USE_VULKAN_DISPLAY_KHR)
@@ -378,13 +377,13 @@ if(NOT MSVC)
 		endif()
 	endif()
 
-	set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -g -D_DEBUG")
+	set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -D_DEBUG")
 	set(CMAKE_CXX_FLAGS_MINSIZEREL "${CMAKE_CXX_FLAGS_MINSIZEREL} -Os -D_NDEBUG")
-	set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -O2 -D_NDEBUG")
+	set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -D_NDEBUG")
 	set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "${CMAKE_CXX_FLAGS_RELWITHDEBINFO} -O2 -g -D_NDEBUG")
-	set(CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG} -g -D_DEBUG")
+	set(CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG} -D_DEBUG")
 	set(CMAKE_C_FLAGS_MINSIZEREL "${CMAKE_C_FLAGS_MINSIZEREL} -Os -D_NDEBUG")
-	set(CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} -O2 -D_NDEBUG")
+	set(CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} -D_NDEBUG")
 	set(CMAKE_C_FLAGS_RELWITHDEBINFO "${CMAKE_C_FLAGS_RELWITHDEBINFO} -O2 -g -D_NDEBUG")
 
 	# Enable checking printf-like format strings (also works for logging functions)
@@ -1125,7 +1124,7 @@ else()
 endif()
 
 # Arm platforms require at least libpng17.
-if(ANDROID OR ARMV7 OR ARM64 OR ARM OR IOS)
+if(ANDROID OR IOS)
 	set(PNG_REQUIRED_VERSION 1.7)
 else()
 	set(PNG_REQUIRED_VERSION 1.6)