Work around surprise x264 compile error

On 32 bit Android. This used to work fine earlier this week, but
suddenly this warning about an implicitly declared function turned into
an error. We now revert it back to a warning.

.github/scripts/build-ffmpeg.cmake

@@ -165,6 +165,29 @@ if(LIBVPX)
 endif()
 
 if(LIBX264)
+	set(x264_configure_args
+		--enable-static
+		--enable-pic
+		--disable-lavf
+		--disable-swscale
+		--disable-avs
+		--disable-ffms
+		--disable-gpac
+		--disable-lsmash
+		--disable-bashcompletion
+		--disable-cli
+		--enable-strip
+	)
+
+	# Configure only checks if *linkage* of functions works, but not if they're
+	# actually present in any headers. This causes weird compile errors about
+	# fseeko and ftello not being present on 32 bit Android. The code appears
+	# to work fine though, so either this doesn't matter or we don't hit that
+	# code. So we just disable the error and carry on.
+	if(ANDROID AND TARGET_ARCH STREQUAL "arm32")
+		list(APPEND x264_configure_args "--extra-cflags=-Wno-error=implicit-function-declaration")
+	endif()
+
 	build_dependency(x264 ${LIBX264} ${BUILD_TYPE}
 		URL https://code.videolan.org/videolan/x264/-/archive/@version@/x264-@[email protected]
 		TARGET_ARCH "${TARGET_ARCH}"
@@ -174,18 +197,7 @@ if(LIBX264)
 		ALL_PLATFORMS
 			AUTOMAKE
 				ASSIGN_HOST ASSIGN_PREFIX WIN32_CC_CL
-				ALL
-					--enable-static
-					--enable-pic
-					--disable-lavf
-					--disable-swscale
-					--disable-avs
-					--disable-ffms
-					--disable-gpac
-					--disable-lsmash
-					--disable-bashcompletion
-					--disable-cli
-					--enable-strip
+				ALL ${x264_configure_args}
 	)
 endif()