alcaro/flips clang error

error.txt

~/git $ cd flips
~/git/flips $ ./make.sh
GTK+ (1/3)
rm: cannot remove 'obj/*': No such file or directory
rm: cannot remove 'flips': No such file or directory
Package gtk+-3.0 was not found in the pkg-config search path.
Perhaps you should add the directory containing `gtk+-3.0.pc'
to the PKG_CONFIG_PATH environment variable
No package 'gtk+-3.0' found
Makefile:60: pkg-config can't find gtk+-3.0, or pkg-config itself can't be found
Makefile:61: if you have the needed files installed, specify their locations and names with `make GTKFLAGS='-I/usr/include' GTKLIBS='-L/usr/lib -lgtk''
Makefile:62: if not, the package names under Debian and derivates are `pkg-config libgtk-3-dev'; for other distros, consult a search engine
Makefile:67: switching to CLI build
g++ /data/data/com.termux/files/home/git/flips/crc32.cpp /data/data/com.termux/files/home/git/flips/flips-cli.cpp /data/data/com.termux/files/home/git/flips/flips-gtk.cpp /data/data/com.termux/files/home/git/flips/flips-w32.cpp /data/data/com.termux/files/home/git/flips/flips.cpp /data/data/com.termux/files/home/git/flips/libbps-suf.cpp /data/data/com.termux/files/home/git/flips/libbps.cpp /data/data/com.termux/files/home/git/flips/libips.cpp /data/data/com.termux/files/home/git/flips/libups.cpp /data/data/com.termux/files/home/git/flips/libdivsufsort-2.0.1/lib/divsufsort.c /data/data/com.termux/files/home/git/flips/libdivsufsort-2.0.1/lib/sssort.c /data/data/com.termux/files/home/git/flips/libdivsufsort-2.0.1/lib/trsort.c -std=c++98 -fno-rtti -fno-exceptions -DNDEBUG -Wall -DFLIPS_CLI -I/data/data/com.termux/files/home/git/flips/libdivsufsort-2.0.1/include -DHAVE_CONFIG_H -D__STDC_FORMAT_MACROS  -Wall -O3 -flto -fuse-linker-plugin -fomit-frame-pointer -fmerge-all-constants -fvisibility=hidden -fno-exceptions -fno-unwind-tables -fno-asynchronous-unwind-tables -ffunction-sections -fdata-sections -Wl,--gc-sections -fprofile-dir=obj/ -Wl,-z,relro,-z,now,--as-needed,--hash-style=gnu,--relax -fprofile-generate -lgcov   -oflips
clang-13: warning: treating 'c' input as 'c++' when in C++ mode, this behavior is deprecated [-Wdeprecated]
clang-13: warning: treating 'c' input as 'c++' when in C++ mode, this behavior is deprecated [-Wdeprecated]
clang-13: warning: treating 'c' input as 'c++' when in C++ mode, this behavior is deprecated [-Wdeprecated]
clang-13: warning: optimization flag '-fuse-linker-plugin' is not supported [-Wignored-optimization-argument]
clang-13: warning: optimization flag '-fuse-linker-plugin' is not supported [-Wignored-optimization-argument]
clang-13: warning: optimization flag '-fuse-linker-plugin' is not supported [-Wignored-optimization-argument]
clang-13: warning: optimization flag '-fuse-linker-plugin' is not supported [-Wignored-optimization-argument]
clang-13: warning: optimization flag '-fuse-linker-plugin' is not supported [-Wignored-optimization-argument]
clang-13: warning: optimization flag '-fuse-linker-plugin' is not supported [-Wignored-optimization-argument]
clang-13: warning: optimization flag '-fuse-linker-plugin' is not supported [-Wignored-optimization-argument]
clang-13: warning: optimization flag '-fuse-linker-plugin' is not supported [-Wignored-optimization-argument]
clang-13: warning: optimization flag '-fuse-linker-plugin' is not supported [-Wignored-optimization-argument]
clang-13: warning: optimization flag '-fuse-linker-plugin' is not supported [-Wignored-optimization-argument]
clang-13: warning: optimization flag '-fuse-linker-plugin' is not supported [-Wignored-optimization-argument]
clang-13: warning: optimization flag '-fuse-linker-plugin' is not supported [-Wignored-optimization-argument]
ld.lld: error: unknown argument '--relax'
ld.lld: error: unable to find library -lgcov
clang-13: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [Makefile:95: flips] Error 1
~/git/flips $