[ffmpeg] add if guard, fix library ordering on linux, minor clean up (#14360)

* [ffmpeg] add 'if(NOT FFMPEG_FOUND)' guard to FindFFMPEG script

* [ffmpeg] fix link order on x64-linux (dependencies must come after the library that needs the dependency)

* [ffmpeg] bump port version

2 files changed, 16 insertions, 12 deletions

diff --git a/ports/ffmpeg/CONTROL b/ports/ffmpeg/CONTROL
index 3a42c7807..32520c8ed 100644
--- a/ports/ffmpeg/CONTROL
+++ b/ports/ffmpeg/CONTROL
@@ -1,6 +1,6 @@
 Source: ffmpeg
 Version: 4.3.1
-Port-Version: 5
+Port-Version: 6
 Homepage: https://ffmpeg.org
 Description: a library to decode, encode, transcode, mux, demux, stream, filter and play pretty much anything that humans and machines have created.
   FFmpeg is the leading multimedia framework, able to decode, encode, transcode, mux, demux, stream, filter and play pretty much anything that humans and machines have created. It supports the most obscure ancient formats up to the cutting edge. No matter if they were designed by some standards committee, the community or a corporation. It is also highly portable: FFmpeg compiles, runs, and passes our testing infrastructure FATE across Linux, Mac OS X, Microsoft Windows, the BSDs, Solaris, etc. under a wide variety of build environments, machine architectures, and configurations.
diff --git a/ports/ffmpeg/FindFFMPEG.cmake.in b/ports/ffmpeg/FindFFMPEG.cmake.in
index 03dfcea0f..57e5315b8 100644
--- a/ports/ffmpeg/FindFFMPEG.cmake.in
+++ b/ports/ffmpeg/FindFFMPEG.cmake.in
@@ -25,9 +25,11 @@
 #
 #
 
-include(${CMAKE_ROOT}/Modules/FindPackageHandleStandardArgs.cmake)
-include(${CMAKE_ROOT}/Modules/SelectLibraryConfigurations.cmake)
-include(${CMAKE_ROOT}/Modules/CMakeFindDependencyMacro.cmake)
+include(FindPackageHandleStandardArgs)
+include(SelectLibraryConfigurations)
+include(CMakeFindDependencyMacro)
+
+if(NOT FFMPEG_FOUND)
 
 function(select_library_configurations_from_names)
   cmake_parse_arguments(_slc "" "BASENAME" "NAMES;NAMES_RELEASE;NAMES_DEBUG" ${ARGN})
@@ -60,7 +62,7 @@ function(select_library_configurations_from_targets)
   set(${_slc_BASENAME}_LIBRARIES ${${_slc_BASENAME}_LIBRARIES} PARENT_SCOPE)
 endfunction()
 
-set(FFMPEG_VERSION "4.2")
+set(FFMPEG_VERSION "4.3.1")
 
 find_dependency(Threads)
 if(UNIX)
@@ -259,22 +261,21 @@ if(APPLE)
   list(APPEND FFMPEG_PLATFORM_DEPENDENT_LIBS ${VT_UNIT} ${AT_UNIT} ${SEC_UNIT} ${CF_UNIT} ${CM_UNIT} ${CV_UNIT})
 endif()
 
-if(@ENABLE_AVCODEC@)
-  FFMPEG_FIND(libavcodec    avcodec    avcodec.h)
-endif()
 if(@ENABLE_AVDEVICE@)
   FFMPEG_FIND(libavdevice   avdevice   avdevice.h)
 endif()
-if(@ENABLE_AVFILTER@)
-  FFMPEG_FIND(libavfilter   avfilter   avfilter.h)
-endif()
 if(@ENABLE_AVFORMAT@)
   FFMPEG_FIND(libavformat   avformat   avformat.h)
 endif()
+if(@ENABLE_AVCODEC@)
+  FFMPEG_FIND(libavcodec    avcodec    avcodec.h)
+endif()
+if(@ENABLE_AVFILTER@)
+  FFMPEG_FIND(libavfilter   avfilter   avfilter.h)
+endif()
 if(@ENABLE_AVRESAMPLE@)
   FFMPEG_FIND(libavresample avresample avresample.h)
 endif()
-FFMPEG_FIND(libavutil       avutil     avutil.h)
 if(@ENABLE_POSTPROC@)
   FFMPEG_FIND(libpostproc   postproc   postprocess.h)
 endif()
@@ -284,6 +285,7 @@ endif()
 if(@ENABLE_SWSCALE@)
   FFMPEG_FIND(libswscale    swscale    swscale.h)
 endif()
+FFMPEG_FIND(libavutil       avutil     avutil.h)
 
 if (FFMPEG_libavutil_FOUND)
   list(REMOVE_DUPLICATES FFMPEG_INCLUDE_DIRS)
@@ -325,3 +327,5 @@ if (FFMPEG_libavutil_FOUND)
 endif()
 
 find_package_handle_standard_args(FFMPEG REQUIRED_VARS FFMPEG_LIBRARIES FFMPEG_LIBRARY_DIRS FFMPEG_INCLUDE_DIRS)
+
+endif()