Issues in the build process

[cerasumat]

Hi, got some ERROR in the build process:
After make by emscripten (emmake make BUILDTYPE=Release -j8), I got all of the .a files in my 'out/Release/obj.target/' path, like libpdfium.a,libfdrm.a etc.
Then call the emscripten:

"em++
-Oz
--llvm-lto 1
--memory-init-file 1
-s EXPORTED_FUNCTIONS="['_PDFiumJS_init', '_PDFiumJS_Doc_new', '_PDFiumJS_Doc_delete', '_PDFiumJS_Doc_get_page_count', '_PDFiumJS_Doc_get_page', '_PDFiumJS_Page_get_width', '_PDFiumJS_Page_get_height', '_PDFiumJS_Page_get_bitmap', '_PDFiumJS_Bitmap_get_buffer', '_PDFiumJS_Bitmap_get_stride', '_PDFiumJS_Bitmap_destroy', '_PDFiumJS_Page_destroy']"
--js-library pdfium.js/pdfium.js.lib.js
-o web/pdfium.js
-Wl,--start-group out/Release/obj.target/pdfium_js/pdfium.js/pdfium.js.o out/Release/obj.target/libpdfium.a out/Release/obj.target/libfdrm.a out/Release/obj.target/libfpdfdoc.a out/Release/obj.target/libfpdfapi.a out/Release/obj.target/libfpdftext.a out/Release/obj.target/libformfiller.a out/Release/obj.target/libfxcodec.a out/Release/obj.target/libfxcrt.a out/Release/obj.target/libfxedit.a out/Release/obj.target/libfxge.a out/Release/obj.target/libpdfwindow.a -Wl,--end-group"
(Copy from the build.sh).


And then got the following ERROR hints:
shared:ERROR: out/Release/obj.target/libpdfium.a: Unknown format, not a static library!

And I try to edit the pdfium.gyp, all the target configuration 'type' is 'static_library', and then I try to specified the 'libraries': [ 'out/Release/obj.target/libfdrm.a ' ], of all the targets, seems not work, still got the same ERROR hints.

Any ideas? Thanks a lot.

[cerasumat]

btw, my host os is CentOS7, and my emscripten env is a Debian based docker image which worked fine.