perl: SIGSEGV on start if LC_ALL is unset

Maintainer: Esaaprilia Salsabila
Environment: ARMv7 Processor rev 4 (v7l), custom OpenWRT fw

Description:

• perl always crashes on startup after upgrade

GDB output:

Reading symbols from ./build_dir/target-arm_cortex-a15+neon-vfpv4_musl_eabi/perl/perl-5.40.0/perl...
0xb6fe69c8 in _dlstart () from /home/egorenar/Repositories/openwrt-rel/scripts/../staging_dir/target-arm_cortex-a15+neon-vfpv4_musl_eabi/root-alpine/lib/ld-musl-armhf.so.1
=> 0xb6fe69c8 <_dlstart+0>:     e3a0b000        mov     r11, #0
(gdb) r
Starting program: /home/egorenar/Repositories/openwrt-rel/build_dir/target-arm_cortex-a15+neon-vfpv4_musl_eabi/perl/perl-5.40.0/perl

Program received signal SIGSEGV, Segmentation fault.
0xb6fd8d18 in strlen (s=<optimized out>) at src/string/strlen.c:17
17              for (w = (const void *)s; !HASZERO(*w); w++);
   0xb6fd8d0c <strlen+52>:      e308e080        movw    lr, #32896      @ 0x8080
   0xb6fd8d10 <strlen+56>:      e34f4efe        movt    r4, #65278      @ 0xfefe
   0xb6fd8d14 <strlen+60>:      e348e080        movt    lr, #32896      @ 0x8080
=> 0xb6fd8d18 <strlen+64>:      e593c000        ldr     r12, [r3]
   0xb6fd8d1c <strlen+68>:      e1a02003        mov     r2, r3
   0xb6fd8d20 <strlen+72>:      e2833004        add     r3, r3, #4
   0xb6fd8d24 <strlen+76>:      e08c1004        add     r1, r12, r4
   0xb6fd8d28 <strlen+80>:      e1c1100c        bic     r1, r1, r12
   0xb6fd8d2c <strlen+84>:      e111000e        tst     r1, lr
   0xb6fd8d30 <strlen+88>:      0afffff8        beq     0xb6fd8d18 <strlen+64>
   0xb6fd8d34 <strlen+92>:      e1a03002        mov     r3, r2
(gdb) bt
#0  0xb6fd8d18 in strlen (s=<optimized out>) at src/string/strlen.c:17
#1  0xb6e3265c in Perl_sv_vcatpvfn_flags ()
   from /home/egorenar/Repositories/openwrt-rel/scripts/../staging_dir/target-arm_cortex-a15+neon-vfpv4_musl_eabi/root-alpine/usr/lib/perl5/5.40/CORE/libperl.so
#2  0xb6e3265c in Perl_sv_vcatpvfn_flags ()
   from /home/egorenar/Repositories/openwrt-rel/scripts/../staging_dir/target-arm_cortex-a15+neon-vfpv4_musl_eabi/root-alpine/usr/lib/perl5/5.40/CORE/libperl.so
#3  0xb6e3265c in Perl_sv_vcatpvfn_flags ()
   from /home/egorenar/Repositories/openwrt-rel/scripts/../staging_dir/target-arm_cortex-a15+neon-vfpv4_musl_eabi/root-alpine/usr/lib/perl5/5.40/CORE/libperl.so
#4  0xb6e3265c in Perl_sv_vcatpvfn_flags ()
   from /home/egorenar/Repositories/openwrt-rel/scripts/../staging_dir/target-arm_cortex-a15+neon-vfpv4_musl_eabi/root-alpine/usr/lib/perl5/5.40/CORE/libperl.so
#5  0xb6e3265c in Perl_sv_vcatpvfn_flags ()
   from /home/egorenar/Repositories/openwrt-rel/scripts/../staging_dir/target-arm_cortex-a15+neon-vfpv4_musl_eabi/root-alpine/usr/lib/perl5/5.40/CORE/libperl.so
#6  0xb6e3265c in Perl_sv_vcatpvfn_flags ()
   from /home/egorenar/Repositories/openwrt-rel/scripts/../staging_dir/target-arm_cortex-a15+neon-vfpv4_musl_eabi/root-alpine/usr/lib/perl5/5.40/CORE/libperl.so
#7  0xb6e3265c in Perl_sv_vcatpvfn_flags ()
   from /home/egorenar/Repositories/openwrt-rel/scripts/../staging_dir/target-arm_cortex-a15+neon-vfpv4_musl_eabi/root-alpine/usr/lib/perl5/5.40/CORE/libperl.so
#8  0xb6e3265c in Perl_sv_vcatpvfn_flags ()
   from /home/egorenar/Repositories/openwrt-rel/scripts/../staging_dir/target-arm_cortex-a15+neon-vfpv4_musl_eabi/root-alpine/usr/lib/perl5/5.40/CORE/libperl.so
#9  0xb6e3265c in Perl_sv_vcatpvfn_flags ()
   from /home/egorenar/Repositories/openwrt-rel/scripts/../staging_dir/target-arm_cortex-a15+neon-vfpv4_musl_eabi/root-alpine/usr/lib/perl5/5.40/CORE/libperl.so
#10 0xb6e3265c in Perl_sv_vcatpvfn_flags ()

Reproduce the startup crash on the reported ARMv7 OpenWrt environment with LC_ALL unset, then inspect the provided GDB backtrace through libperl.so, Perl_sv_vcatpvfn_flags, and musl's src/string/strlen.c. Done means Perl starts without SIGSEGV in this configuration; the report names no repository source file or test to edit.