Rebuild with lto enabled

[Andreas Hasenack]

frr was placed in lto-disabled-list because it failed to build[1] in the first round of lto testing, but turns out that failure is not lto related:

checking python interpreter python3... /usr/bin/python3 (python3)
checking whether /usr/bin/python3.9-config is available... yes
checking whether /usr/bin/python3.9-config provides a working build environment... no
checking whether pkg-config python-3.9 is available... yes
checking whether pkg-config python-3.9 provides a working build environment... no
checking whether /usr/bin/python3.9-config is available... yes
checking whether /usr/bin/python3.9-config provides a working build environment... no
checking whether pkg-config python-3.9 is available... yes
checking whether pkg-config python-3.9 provides a working build environment... no
configure: error: PYTHON (/usr/bin/python3) explicitly specified but development environment not working

I just tried a rebuild of frr 8.1 from jammy, with lto enabled, and it built fine, therefore we can remove it from the lto-disabled-list package.

1. https://launchpadlibrarian.net/519568994/buildlog_ubuntu-hirsute-amd64.frr_7.4-1_BUILDING.txt.gz

[Andreas Hasenack (ahasenack)]

https://launchpad.net/ubuntu/+source/frr/8.1-1ubuntu1 has lto enabled:

From the build log at https://launchpadlibrarian.net/590177409/buildlog_ubuntu-jammy-amd64.frr_8.1-1ubuntu1_BUILDING.txt.gz:

compiler flags : -g -O2 -ffile-prefix-map=/<<PKGBUILDDIR>>=. -flto=auto -ffat-lto-objects -flto=auto -ffat-lto-objects -fstack-protector-strong -Wformat -Werror=format-security -fno-omit-frame-pointer -funwind-tables -Wall -Wextra -Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations -Wpointer-arith -Wbad-function-cast -Wwrite-strings -Wundef -Wno-unused-result -Wno-unused-parameter -Wno-missing-field-initializers

linker flags : -Wl,-Bsymbolic-functions -flto=auto -ffat-lto-objects -flto=auto -Wl,-z,relro -Wl,-z,now -lcrypt -lelf -ljson-c -lrt -lcap -lreadline -lm