perlPackages.BoostGeometryUtils: unbreak build

Set LD=$CC to fix this build error:

...
ExtUtils::Mkbootstrap::Mkbootstrap('blib/arch/auto/Boost/Geometry/Utils/Utils.bs')
ld -shared -O2 -L/nix/store/sgjc1147vi5hd57ck9xgck5xjkydg5lz-glibc-2.25/lib -fstack-protector-strong -o blib/arch/auto/Boost/Geometry/Utils/Utils.so buildtmp/Utils.o -lstdc++
buildtmp/Utils.o: In function `_GLOBAL__sub_I_Utils.c':
Utils.c:(.text.startup+0x1a): undefined reference to `__dso_handle'
/nix/store/yf4p5w2v4h4i8rja9zw1akp007av624j-binutils-2.28.1/bin/ld: buildtmp/Utils.o: relocation R_X86_64_PC32 against undefined hidden symbol `__dso_handle' can not be used when making a shared object
/nix/store/yf4p5w2v4h4i8rja9zw1akp007av624j-binutils-2.28.1/bin/ld: final link failed: Bad value
error building blib/arch/auto/Boost/Geometry/Utils/Utils.so from buildtmp/Utils.o at /nix/store/7q2hps69zkj501lsmvnd2ry95mmdbh80-perl-5.24.2/lib/perl5/5.24.2/ExtUtils/CBuilder/Base.pm line 321.
builder for ‘/nix/store/bdwqvgxlgcqsmlqfh0d74jkpw96p78kh-perl-Boost-Geometry-Utils-0.15.drv’ failed with exit code 2
error: build of ‘/nix/store/bdwqvgxlgcqsmlqfh0d74jkpw96p78kh-perl-Boost-Geometry-Utils-0.15.drv’ failed

pkgs/top-level/perl-packages.nix

···
       # Fix out of memory error on Perl 5.19.4 and later.
       ../development/perl-modules/boost-geometry-utils-fix-oom.patch
     ];
+    perlPreHook = "export LD=$CC";
   };
 
   BusinessHours = buildPerlPackage rec {