I tried to build with the following *FLAGS to optimize the build: `-flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing`

Note the -Werror=* flags are used to help detect cases where the compiler tries to optimize by assuming UB cannot exist in the source code -- if it does exist, ordinarily the code would be miscompiled, and this says to make the miscompilation a fatal error.

I got this error:
```
/bin/sh ../libtool  --tag=CC   --mode=link x86_64-pc-linux-gnu-gcc  -march=native -fstack-protector-all -O2 -pipe -fdiagnostics-color=always -frecord-gcc-switches -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=3 -fstack-clash-protection -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing  -Wformat -Werror=format-security -Werror=implicit-function-declaration -Werror=implicit-int -Werror=int-conversion -Werror=incompatible-pointer-types -Wno-error=format-security  -Wall -Wbad-function-cast -Wcast-align -Wchar-subscripts -Wdeclaration-after-statement -Wdisabled-optimization -Wendif-labels -Winline -Wmissing-declarations -Wmissing-prototypes -Wnested-externs -Wno-sign-compare -Wpointer-arith -Wshadow -Wstrict-prototypes -Wundef -Wunused -Wwrite-strings  -Wl,-O1 -Wl,--as-needed -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing -Wl,--defsym=__gentoo_check_ldflags__=0 -Wl,--undefined-version -o cdda-player cdda-player.o cddb.o getopt.o getopt1.o ../lib/driver/libcdio.la  -lncurses -ltinfo -lm
libtool: link: x86_64-pc-linux-gnu-gcc -march=native -fstack-protector-all -O2 -pipe -fdiagnostics-color=always -frecord-gcc-switches -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=3 -fstack-clash-protection -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing -Wformat -Werror=format-security -Werror=implicit-function-declaration -Werror=implicit-int -Werror=int-conversion -Werror=incompatible-pointer-types -Wno-error=format-security -Wall -Wbad-function-cast -Wcast-align -Wchar-subscripts -Wdeclaration-after-statement -Wdisabled-optimization -Wendif-labels -Winline -Wmissing-declarations -Wmissing-prototypes -Wnested-externs -Wno-sign-compare -Wpointer-arith -Wshadow -Wstrict-prototypes -Wundef -Wunused -Wwrite-strings -Wl,-O1 -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing -Wl,--defsym=__gentoo_check_ldflags__=0 -Wl,--undefined-version -o .libs/cdda-player cdda-player.o cddb.o getopt.o getopt1.o  -Wl,--as-needed ../lib/driver/.libs/libcdio.so -lncurses -ltinfo -lm
../../libcdio-2.1.0/src/cddb.h:31:20: error: type of 'cddb_opts' does not match original declaration [-Werror=lto-type-mismatch]
   31 | extern cddb_opts_t cddb_opts;
      |                    ^
../../libcdio-2.1.0/src/cddb.c:27:13: note: 'cddb_opts' was previously declared here
   27 | cddb_opts_t cddb_opts;
      |             ^
../../libcdio-2.1.0/src/cddb.c:27:13: note: code may be misoptimized unless '-fno-strict-aliasing' is used
lto1: some warnings being treated as errors
lto-wrapper: fatal error: x86_64-pc-linux-gnu-gcc returned 1 exit status
compilation terminated.
/usr/lib/gcc/x86_64-pc-linux-gnu/13/../../../../x86_64-pc-linux-gnu/bin/ld: error: lto-wrapper failed
collect2: error: ld returned 1 exit status
```

Downstream report: https://bugs.gentoo.org/855701

Full build log is attached.