gcc -Wl,--as-needed -Wl,-z,noexecstack -o /tmp/ffconf.wIRvwFTx/test /tmp/ffconf.wIRvwFTx/test.o
/tmp/ffconf.wIRvwFTx/test.o: In function `foo':
test.c:(.text+0xcf): undefined reference to `cexp'
collect2: error: ld returned 1 exit status
require_pkg_config libopus opus opus_multistream.h opus_multistream_decoder_create
check_pkg_config libopus opus opus_multistream.h opus_multistream_decoder_create
test_pkg_config libopus opus opus_multistream.h opus_multistream_decoder_create
pkg-config --exists --print-errors opus
check_func_headers opus_multistream.h opus_multistream_decoder_create -I/usr/include/opus -lopus
test_ld cc -I/usr/include/opus -lopus
test_cc -I/usr/include/opus
BEGIN /tmp/ffconf.wIRvwFTx/test.c
    1   #include <opus_multistream.h>
    2   #include <stdint.h>
    3   long check_opus_multistream_decoder_create(void) { return (long) opus_multistream_decoder_create; }
    4   int main(void) { int ret = 0;
    5    ret |= ((intptr_t)check_opus_multistream_decoder_create) & 0xFFFF;
    6   return ret; }
END /tmp/ffconf.wIRvwFTx/test.c
gcc -D_ISOC99_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_POSIX_C_SOURCE=200112 -D_XOPEN_SOURCE=600 -std=c11 -fomit-frame-pointer -pthread -I/usr/include/opus -c -o /tmp/ffconf.wIRvwFTx/test.o /tmp/ffconf.wIRvwFTx/test.c
gcc -Wl,--as-needed -Wl,-z,noexecstack -I/usr/include/opus -o /tmp/ffconf.wIRvwFTx/test /tmp/ffconf.wIRvwFTx/test.o -lopus
require_pkg_config libopus opus opus_multistream.h opus_multistream_surround_encoder_create
check_pkg_config libopus opus opus_multistream.h opus_multistream_surround_encoder_create
test_pkg_config libopus opus opus_multistream.h opus_multistream_surround_encoder_create
pkg-config --exists --print-errors opus
check_func_headers opus_multistream.h opus_multistream_surround_encoder_create -I/usr/include/opus -lopus
test_ld cc -I/usr/include/opus -lopus
test_cc -I/usr/include/opus
BEGIN /tmp/ffconf.wIRvwFTx/test.c
    1   #include <opus_multistream.h>
    2   #include <stdint.h>
    3   long check_opus_multistream_surround_encoder_create(void) { return (long) opus_multistream_surround_encoder_create; }
    4   int main(void) { int ret = 0;
    5    ret |= ((intptr_t)check_opus_multistream_surround_encoder_create) & 0xFFFF;
    6   return ret; }
END /tmp/ffconf.wIRvwFTx/test.c
gcc -D_ISOC99_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_POSIX_C_SOURCE=200112 -D_XOPEN_SOURCE=600 -std=c11 -fomit-frame-pointer -pthread -I/usr/include/opus -I/usr/include/opus -c -o /tmp/ffconf.wIRvwFTx/test.o /tmp/ffconf.wIRvwFTx/test.c
/tmp/ffconf.wIRvwFTx/test.c: In function 'check_opus_multistream_surround_encoder_create':
/tmp/ffconf.wIRvwFTx/test.c:3:75: error: 'opus_multistream_surround_encoder_create' undeclared (first use in this function)
 long check_opus_multistream_surround_encoder_create(void) { return (long) opus_multistream_surround_encoder_create; }
                                                                           ^
/tmp/ffconf.wIRvwFTx/test.c:3:75: note: each undeclared identifier is reported only once for each function it appears in
ERROR: opus not found using pkg-config