Build fails with LTO

[eli-schwartz]

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:

x86_64-pc-linux-gnu-gcc  -march=native -fstack-protector-all -O2 -pipe -fdiagnostics-color=always -frecord-gcc-switches -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  -Wl,-O1 -Wl,--as-needed -flto=4 -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing -Wl,--defsym=__gentoo_check_ldflags__=0 -o ros main.o opt.o download.o download_windows.o archive.o archive_windows.o register-commands.o tsv-sbcl-bin.o util.o util_windows.o util-list.o util-string.o util-dir.o util-dir_windows.o util-file.o util-file_windows.o util-system.o util-system_windows.o util-cmdline.o proc-opt.o manual.o manual_windows.o cmd-internal.o cmd-script.o cmd-run.o cmd-run-sbcl.o cmd-run-ccl.o cmd-run-clasp.o cmd-run-clisp.o cmd-run-ecl.o cmd-run-mkcl.o cmd-run-abcl.o cmd-run-cmu.o cmd-run-acl.o cmd-run-lispworks.o cmd-run-npt.o cmd-install.o install-sbcl-bin.o install-sbcl-bin_windows.o resources.o -lcurl 
cmd-run.h:27:13: error: type of ‘register_runtime_options’ does not match original declaration [-Werror=lto-type-mismatch]
   27 | extern LVal register_runtime_options();
      |             ^
register-commands.c:63:18: note: return value type mismatch
   63 | struct proc_opt* register_runtime_options(struct proc_opt* cmd) {
      |                  ^
register-commands.c:63:18: note: ‘register_runtime_options’ was previously declared here
register-commands.c:63:18: 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
make[2]: *** [Makefile:436: ros] Error 1
make[2]: Leaving directory '/var/tmp/portage/dev-lisp/roswell-22.12.14.113/work/roswell-22.12.14.113/src'
make[1]: *** [Makefile:615: all-recursive] Error 1
make: *** [Makefile:438: all] Error 2
 * ERROR: dev-lisp/roswell-22.12.14.113::gentoo failed (compile phase):

Originally reported downstream at https://bugs.gentoo.org/856106
Full build log: build.log