perl: userelocatableinc causes Alpine builds to fail

[egorksv]

Maintainer: @Naoir
Environment: Alpine Linux 3.18, OpenWRT 23.05.5

Description:
During cross-compilation of perl module on Alpine specifically, execution of miniperl fails, as been noted in multiple issues:
#10598

as an example:

make[3]: Entering directory '/root/openwrt-19.07/build_dir/target-mips_24kc_musl/perl/perl-5.28.1'

/bin/ln -s /root/openwrt-19.07/staging_dir/hostpkg/usr/bin/perl miniperl
LD_LIBRARY_PATH=/root/openwrt-19.07/build_dir/target-mips_24kc_musl/perl/perl-5.28.1 ./miniperl -w -Ilib -I. -Idist/Exporter/lib -MExporter -e '<?>' || sh -c 'echo >&2 Failed to build miniperl.  Please run make minitest; exit 1'

Can't locate File/Glob.pm in @INC (you may need to install the File::Glob module) (@INC contains: lib . dist/Exporter/lib ./../lib/perl5/site_perl/5.28.1/x86_64-linux ./../lib/perl5/site_perl/5.28.1 ./../lib/perl5/5.28.1/x86_64-linux ./../lib/perl5/5.28.1) at -e line 1.

This happens due to miniperl being called from perl source directory being cross-compiled, and ./../lib resolves to /root/openwrt-19.07/build_dir/target-mips_24kc_musl/perl/perl-5.28.1/./../lib which at this point does not contain Glob.pm

Removing -Duserelocatableinc from Makefile seems to solve the issue

[egorksv]

Also #6700 - as that needs to be resolved first, unfortunately am unable to reopen that one