[FFmpeg-devel] ffplay failed to build under mingw32 (and under OS X)

[Hanspeter Niederstrasser]

> after "configure: Revert sdl hunk of 4fa18c56. This breaks OSX"
> (http://git.videolan.org/?p=ffmpeg.git;a=commitdiff;h=ca87d439065c705311d0a98076df3c021b187adb)
> ffplay is stopped to build. That happens because of SDL check fail. To
> be more precise it fail in a check:
>
> /.../
> check_func_headers SDL.h SDL_Init $sdl_cflags $sdl_libs &&
> /.../
>
> that give in config.log message:
>
> /.../
> check_func_headers SDL.h SDL_Init
> -I/usr/i686-pc-mingw32/sys-root/mingw/include/SDL -D_GNU_SOURCE=1
> -Dmain=SDL_main -lmingw32 -lSDLmain -lSDL -mwindows
> check_ld -I/usr/i686-pc-mingw32/sys-root/mingw/include/SDL
> -D_GNU_SOURCE=1 -Dmain=SDL_main -lmingw32 -lSDLmain -lSDL -mwindows
> check_cc -I/usr/i686-pc-mingw32/sys-root/mingw/include/SDL
> -D_GNU_SOURCE=1 -Dmain=SDL_main -mwindows
> BEGIN /tmp/ffconf.CKUleDYo.c
>      1 #include <SDL.h>
>      2 long check_SDL_Init(void) { return (long) SDL_Init; }
>      3 int main(void) { return 0; }
> END /tmp/ffconf.CKUleDYo.c
> ccache i686-pc-mingw32-gcc -D_ISOC99_SOURCE -D_POSIX_C_SOURCE=200112
> -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -U__STRICT_ANSI__ --static
> -I/var/www/users/research/ffmpeg/snapshots/build/include -std=c99
> -fno-common -fomit-frame-pointer
> -I/usr/i686-pc-mingw32/sys-root/mingw/include/SDL -D_GNU_SOURCE=1
> -Dmain=SDL_main -mwindows -c -o /tmp/ffconf.PXRBqhG8.o
> /tmp/ffconf.CKUleDYo.c
> /tmp/ffconf.CKUleDYo.c:3:5: error: conflicting types for 'SDL_main'
> /usr/i686-pc-mingw32/sys-root/mingw/include/SDL/SDL_main.h:53:12: note:
> previous declaration of 'SDL_main' was here
> /.../

The same error happens on OS X (10.5/i386 with SDL-1.2.14 built
locally), but presumably also happens on other OS X versions.

My solution was to have check_func_headers() test for the same things
as in the pkg-config based check in the conditional (which does work
on OS X if I force the conditional to not use sdl-config):

diff --git a/configure b/configure
index 2fa0f3a..eda7909 100755
--- a/configure
+++ b/configure
@@ -2937,17 +2937,17 @@ if enabled libdc1394; then
         enable libdc1394_1; } ||
     die "ERROR: No version of libdc1394 found "
 fi

 SDL_CONFIG="${cross_prefix}sdl-config"
 if "${SDL_CONFIG}" --version > /dev/null 2>&1; then
     sdl_cflags=$("${SDL_CONFIG}" --cflags)
     sdl_libs=$("${SDL_CONFIG}" --libs)
-    check_func_headers SDL.h SDL_Init $sdl_cflags $sdl_libs &&
+    check_func_headers SDL_version.h SDL_Linked_Version $sdl_cflags
$sdl_libs &&
     check_cpp_condition SDL.h "(SDL_MAJOR_VERSION<<16 |
SDL_MINOR_VERSION<<8 | SDL_PATCHLEVEL) >= 0x010201" $sdl_cflags &&
     enable sdl &&
     check_struct SDL.h SDL_VideoInfo current_w $sdl_cflags && enable
sdl_video_size
 else
     if check_pkg_config sdl SDL_version.h SDL_Linked_Version; then
         check_cpp_condition SDL.h "(SDL_MAJOR_VERSION<<16 |
SDL_MINOR_VERSION<<8 | SDL_PATCHLEVEL) >= 0x010201" $sdl_cflags &&
         enable sdl &&
         check_struct SDL.h SDL_VideoInfo current_w $sdl_cflags &&
enable sdl_video_size

For the record, I also independently tried Maksym's 2nd patch to
directly modify the check_func_headers function

> -        echo "int main(void) { return 0; }"
> +        echo "int main(int argc, char** argv) { return 0; }"

and that also re-enabled SDL.

Hanspeter

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