[FFmpeg-user] Error compiling ffmpeg 4.1 with librtmp

[Eduardo Alarcón]

Hello,
i'm trying to compile ffmpeg various libs, including librtmp but i have
been unable to. I have done it before, but this is a new system
The last error is always
ERROR: librtmp not found using pkg-config

So i checked the config.log and the last lines are:
require_pkg_config librtmp librtmp librtmp/rtmp.h RTMP_Socket
check_pkg_config librtmp librtmp librtmp/rtmp.h RTMP_Socket
test_pkg_config librtmp librtmp librtmp/rtmp.h RTMP_Socket
pkg-config --exists --print-errors librtmp
check_func_headers librtmp/rtmp.h RTMP_Socket -I/usr/include/p11-kit-1
-lrtmp -lz -lgmp -lgnutls -lz -R/usr/lib/x86_64-linux-gnu -lp11-kit -lgmp
-ltasn1 -lidn -lp11-kit -lz -lhogweed -lgmp -lnettle
test_ld cc -I/usr/include/p11-kit-1 -lrtmp -lz -lgmp -lgnutls -lz
-R/usr/lib/x86_64-linux-gnu -lp11-kit -lgmp -ltasn1 -lidn -lp11-kit -lz
-lhogweed -lgmp -lnettle
test_cc -I/usr/include/p11-kit-1 -R/usr/lib/x86_64-linux-gnu
BEGIN /tmp/ffconf.LARHQ5JE/test.c
    1 #include <librtmp/rtmp.h>
    2 #include <stdint.h>
    3 long check_RTMP_Socket(void) { return (long) RTMP_Socket; }
    4 int main(void) { int ret = 0;
    5 ret |= ((intptr_t)check_RTMP_Socket) & 0xFFFF;
    6 return ret; }
END /tmp/ffconf.LARHQ5JE/test.c
gcc -D_ISOC99_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE
-D_POSIX_C_SOURCE=200112 -D_XOPEN_SOURCE=600 -DPIC
-I/root/ffmpeg_build/include -std=c11 -fomit-frame-pointer -fPIC -pthread
-I/usr/include/harfbuzz -I/usr/include/glib-2.0
-I/usr/lib/x86_64-linux-gnu/glib-2.0/include -I/usr/include/freetype2
-I/usr/include/fribidi -I/usr/include/freetype2
-I/root/ffmpeg_build/include -I/usr/include/freetype2
-I/root/ffmpeg_build/include/opus -I/root/ffmpeg_build/include/opus
-I/usr/include/p11-kit-1 -R/usr/lib/x86_64-linux-gnu -c -o
/tmp/ffconf.LARHQ5JE/test.o /tmp/ffconf.LARHQ5JE/test.c
gcc: error: unrecognized command line option '-R'; did you mean '-R'?
ERROR: librtmp not found using pkg-config

I think the cause is  *gcc: error: unrecognized command line option '-R';
did you mean '-R'?*
but i don't know how to solve it

The configure options are:
# ./configure --prefix=/root/ffmpeg_build --pkg-config-flags=--static
--extra-cflags=-I/root/ffmpeg_build/include
--extra-ldflags=-L/root/ffmpeg_build/lib --bindir=/root/bin
--enable-openssl --enable-gpl --enable-libass --enable-libfdk-aac
--enable-librtmp --enable-libmp3lame --enable-libtheora --enable-libvorbis
--enable-libvpx --enable-libx264 --enable-libfreetype --enable-libopus
--enable-nonfree

Thanks in advance