Build fails on ubuntu 20.04

[Mahdi-Hosseinali]

OS info:

DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=20.04
DISTRIB_CODENAME=focal
DISTRIB_DESCRIPTION="Ubuntu 20.04.4 LTS"
NAME="Ubuntu"
VERSION="20.04.4 LTS (Focal Fossa)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 20.04.4 LTS"
VERSION_ID="20.04"
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
VERSION_CODENAME=focal
UBUNTU_CODENAME=focal

build steps:

mkdir build
cd build/
cmake -DCMAKE_BUILD_TYPE=Release ..
-- The C compiler identification is GNU 9.4.0
-- The CXX compiler identification is GNU 9.4.0
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /usr/bin/cc - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/c++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- CMAKE_BUILD_TYPE: Release
-- CMAKE_INSTALL_PREFIX: /usr/local
-- CMAKE_POSITION_INDEPENDENT_CODE: ON
-- BUILD_SHARED_LIBS: ON
-- BUILD_TESTING: ON
-- Performing Test wav_has_c_flag_-fno-strict-aliasing
-- Performing Test wav_has_c_flag_-fno-strict-aliasing - Success
-- Performing Test wav_has_c_flag_-Wall
-- Performing Test wav_has_c_flag_-Wall - Success
-- Performing Test wav_has_c_flag_-Wcast-align
-- Performing Test wav_has_c_flag_-Wcast-align - Success
-- Performing Test wav_has_c_flag_-Wduplicated-branches
-- Performing Test wav_has_c_flag_-Wduplicated-branches - Success
-- Performing Test wav_has_c_flag_-Wduplicated-cond
-- Performing Test wav_has_c_flag_-Wduplicated-cond - Success
-- Performing Test wav_has_c_flag_-Wextra
-- Performing Test wav_has_c_flag_-Wextra - Success
-- Performing Test wav_has_c_flag_-Wformat=2
-- Performing Test wav_has_c_flag_-Wformat=2 - Success
-- Performing Test wav_has_c_flag_-Wmissing-include-dirs
-- Performing Test wav_has_c_flag_-Wmissing-include-dirs - Success
-- Performing Test wav_has_c_flag_-Wnarrowing
-- Performing Test wav_has_c_flag_-Wnarrowing - Success
-- Performing Test wav_has_c_flag_-Wpointer-arith
-- Performing Test wav_has_c_flag_-Wpointer-arith - Success
-- Performing Test wav_has_c_flag_-Wshadow
-- Performing Test wav_has_c_flag_-Wshadow - Success
-- Performing Test wav_has_c_flag_-Wuninitialized
-- Performing Test wav_has_c_flag_-Wuninitialized - Success
-- Performing Test wav_has_c_flag_-Wwrite-strings
-- Performing Test wav_has_c_flag_-Wwrite-strings - Success
-- Performing Test wav_has_c_flag_-Wno-multichar
-- Performing Test wav_has_c_flag_-Wno-multichar - Success
-- Performing Test wav_has_c_flag_-Wno-format-nonliteral
-- Performing Test wav_has_c_flag_-Wno-format-nonliteral - Success
-- Performing Test wav_has_c_flag_-Wno-format-truncation
-- Performing Test wav_has_c_flag_-Wno-format-truncation - Success
-- Performing Test wav_has_c_flag_-Werror=discarded-qualifiers
-- Performing Test wav_has_c_flag_-Werror=discarded-qualifiers - Success
-- Performing Test wav_has_c_flag_-Werror=ignored-qualifiers
-- Performing Test wav_has_c_flag_-Werror=ignored-qualifiers - Success
-- Performing Test wav_has_c_flag_-Werror=implicit
-- Performing Test wav_has_c_flag_-Werror=implicit - Success
-- Performing Test wav_has_c_flag_-Werror=implicit-function-declaration
-- Performing Test wav_has_c_flag_-Werror=implicit-function-declaration - Success
-- Performing Test wav_has_c_flag_-Werror=implicit-int
-- Performing Test wav_has_c_flag_-Werror=implicit-int - Success
-- Performing Test wav_has_c_flag_-Werror=init-self
-- Performing Test wav_has_c_flag_-Werror=init-self - Success
-- Performing Test wav_has_c_flag_-Werror=incompatible-pointer-types
-- Performing Test wav_has_c_flag_-Werror=incompatible-pointer-types - Success
-- Performing Test wav_has_c_flag_-Werror=int-conversion
-- Performing Test wav_has_c_flag_-Werror=int-conversion - Success
-- Performing Test wav_has_c_flag_-Werror=return-type
-- Performing Test wav_has_c_flag_-Werror=return-type - Success
-- Performing Test wav_has_c_flag_-Werror=strict-prototypes
-- Performing Test wav_has_c_flag_-Werror=strict-prototypes - Success
-- Configuring done
-- Generating done
-- Build files have been written to: ~/libwav/build

make
[ 25%] Building C object CMakeFiles/wav.dir/src/wav.c.o
[ 50%] Linking C shared library libwav.so
[ 50%] Built target wav
[ 75%] Building C object tests/write_f32/CMakeFiles/write-f32.dir/main.c.o
[100%] Linking C executable write-f32
/usr/bin/ld: CMakeFiles/write-f32.dir/main.c.o: in function `main':
main.c:(.text.startup+0x37): undefined reference to `wav_open'
/usr/bin/ld: main.c:(.text.startup+0x47): undefined reference to `wav_set_format'
/usr/bin/ld: main.c:(.text.startup+0x54): undefined reference to `wav_set_num_channels'
/usr/bin/ld: main.c:(.text.startup+0x61): undefined reference to `wav_set_sample_rate'
/usr/bin/ld: main.c:(.text.startup+0x71): undefined reference to `wav_write'
/usr/bin/ld: main.c:(.text.startup+0x79): undefined reference to `wav_close'
collect2: error: ld returned 1 exit status
make[2]: *** [tests/write_f32/CMakeFiles/write-f32.dir/build.make:98: tests/write_f32/write-f32] Error 1
make[1]: *** [CMakeFiles/Makefile2:882: tests/write_f32/CMakeFiles/write-f32.dir/all] Error 2
make: *** [Makefile:166: all] Error 2