Compilation error with buildroot

[frodo13]

I've start to make a buildroot package for hypseus for a raspberry target.
I get this error:

/usr/bin/make -j9 -C /home/fredo/projets/rpi/output/build/hypseus-c6af13b/src
[ 6%] Built target libmpeg2
[ 8%] Built target cpu_x86
[ 10%] Built target plog
[ 12%] Built target timer
[ 13%] Linking CXX shared library libvldp.so
[ 26%] Built target ldp-in
[ 26%] Built target video
../3rdparty/lib/libmpeg2.a: error adding symbols: File format not recognized
collect2: error: ld returned 1 exit status
vldp/CMakeFiles/vldp.dir/build.make:147: recipe for target 'vldp/libvldp.so' failed
make[5]: *** [vldp/libvldp.so] Error 1
CMakeFiles/Makefile2:841: recipe for target 'vldp/CMakeFiles/vldp.dir/all' failed
make[4]: *** [vldp/CMakeFiles/vldp.dir/all] Error 2
Makefile:105: recipe for target 'all' failed
make[3]: *** [all] Error 2
package/pkg-generic.mk:234: recipe for target '/home/fredo/projets/rpi/output/build/hypseus-c6af13b/.stamp_built' failed
make[2]: *** [/home/fredo/projets/rpi/output/build/hypseus-c6af13b/.stamp_built] Error 2
Makefile:16: recipe for target '_all' failed
make[1]: *** [_all] Error 2
Makefile:67: recipe for target 'build' failed
make: *** [build] Error 2

I am not familiar with cmake (I usually use autotool), is there somes conf_opts to pass to cmake?

I use gcc 4.9.4 for arm with cmake 3.7.2

PS:
I've made two patchs before, to prevent compile issues :
The first one is :
--- hypseus-c6af13b/src/io/CMakeLists.txt 2017-11-02 17:41:39.000000000 +0100
+++ hypseus-static/src/io/CMakeLists.txt 2018-02-15 14:42:47.995940928 +0100
@@ -16,7 +16,7 @@ set( LIB_HEADERS
find_package(ZLIB REQUIRED)
include_directories( ${ZLIB_INCLUDE_DIRS} )

-add_library( io ${LIB_SOURCES} ${LIB_HEADERS} )
+add_library( io STATIC ${LIB_SOURCES} ${LIB_HEADERS} )
target_link_libraries( io ldp-out game plog ${ZLIB_LIBRARIES} )
if( WIN32 )
target_link_libraries( io ws2_32 )
--- hypseus-c6af13b/src/game/CMakeLists.txt 2017-11-02 17:41:39.000000000 +0100
+++ hypseus-static/src/game/CMakeLists.txt 2018-02-15 14:43:20.307942608 +0100
@@ -69,7 +69,7 @@ endif( BUILD_SINGE )

ignore gcc: warning: promoted ~unsigned is always non-zero [-Wsign-compare] (do_nmi coin check)

set_source_files_properties( laireuro.cpp PROPERTIES COMPILE_FLAGS -Wno-sign-compare)

-add_library( game ${LIB_SOURCES} ${LIB_HEADERS} )
+add_library( game STATIC ${LIB_SOURCES} ${LIB_HEADERS} )
target_link_libraries( game sound scoreboard video io plog )
if( BUILD_SINGE )
target_link_libraries( game singeproxy )
--- hypseus-c6af13b/src/scoreboard/CMakeLists.txt 2017-11-02 17:41:39.000000000 +0100
+++ hypseus-static/src/scoreboard/CMakeLists.txt 2018-02-15 14:43:35.459943395 +0100
@@ -18,5 +18,5 @@ set( LIB_HEADERS
scoreboard_interface.h
)

-add_library( scoreboard ${LIB_SOURCES} ${LIB_HEADERS} )
+add_library( scoreboard STATIC ${LIB_SOURCES} ${LIB_HEADERS} )
target_link_libraries( scoreboard io )
--- hypseus-c6af13b/src/ldp-out/CMakeLists.txt 2017-11-02 17:41:39.000000000 +0100
+++ hypseus-static/src/ldp-out/CMakeLists.txt 2018-02-15 14:42:26.095939790 +0100
@@ -15,5 +15,5 @@ set( LIB_HEADERS
PKG_SEARCH_MODULE(VORBISFILE REQUIRED vorbisfile)
include_directories( ${VORBISFILE_INCLUDE_DIRS} )

-add_library( ldp-out ${LIB_SOURCES} ${LIB_HEADERS} )
+add_library( ldp-out STATIC ${LIB_SOURCES} ${LIB_HEADERS} )
target_link_libraries( ldp-out vldp game ${VORBISFILE_LIBRARIES} ${SDL2_LIBRARY} )

the second is :
--- hypseus-c6af13b/src/video/video.cpp 2017-11-02 17:41:39.000000000 +0100
+++ hypseus-unused/src/video/video.cpp 2018-02-16 10:16:39.190208578 +0100
@@ -447,7 +446,7 @@ void draw_overlay_leds(unsigned int valu
// Draw LDP1450 overlay characters to the screen (added by Brad O.)
void draw_singleline_LDP1450(char *LDP1450_String, int start_x, int y, SDL_Surface *overlay)
{

• SDL_Rect src, dest;

• SDL_Rect dest;

  int i = 0;
  int value = 0;
  @@ -459,10 +458,6 @@ void draw_singleline_LDP1450(char *LDP14
  dest.w = OVERLAY_LDP1450_WIDTH;
  dest.h = OVERLAY_LDP1450_HEIGHT;

• src.y = 0;

• src.w = OVERLAY_LDP1450_WIDTH;

• src.h = OVERLAY_LDP1450_WIDTH;

• LDP1450_strlen = strlen(LDP1450_String);

  if (!LDP1450_strlen) // if a blank line is sent, we must blank out the

[lmerckx]

Hello, I have the same error.
It seems to work by replacing

if( CMAKE_CROSS_COMPILING )
by
if( CMAKE_CROSSCOMPILING )

in src/cmake/modules/BuildLibMPEG2.cmake