This is perl 5, version 18, subversion 2 (v5.18.2) built for darwin-thread-multi-2level
(with 2 registered patches, see perl -V for more detail)

##</code><code>##

$ cc -I/System/Library/Perl/5.18/darwin-thread-multi-2level/CORE -DXS_VERSION="0.011" -DVERSION="0.011" -c -arch x86_64 -arch i386 -g -pipe -fno-common -DPERL_DARWIN -fno-strict-aliasing -fstack-protector -Os -o lib/PerlIO/Layers.o lib/PerlIO/Layers.c
lib/PerlIO/Layers.c:249:5: error: expected ')'
    XS_VERSION_BOOTCHECK;
    ^
/System/Library/Perl/5.18/darwin-thread-multi-2level/CORE/XSUB.h:328:61: note: expanded
      from macro 'XS_VERSION_BOOTCHECK'
    Perl_xs_version_bootcheck(aTHX_ items, ax, STR_WITH_LEN(XS_VERSION))
                                                            ^
<command line>:1:20: note: expanded from here
#define XS_VERSION 0.011
                   ^
lib/PerlIO/Layers.c:249:5: note: to match this '('
/System/Library/Perl/5.18/darwin-thread-multi-2level/CORE/XSUB.h:328:48: note: expanded
      from macro 'XS_VERSION_BOOTCHECK'
    Perl_xs_version_bootcheck(aTHX_ items, ax, STR_WITH_LEN(XS_VERSION))
                                               ^
/System/Library/Perl/5.18/darwin-thread-multi-2level/CORE/handy.h:348:26: note: expanded
      from macro 'STR_WITH_LEN'
#define STR_WITH_LEN(s)  ("" s ""), (sizeof(s)-1)
                         ^
1 error generated.

##</code><code>##

$ file `which cc`
/usr/bin/cc: Mach-O 64-bit executable x86_64
$ cc -v
Apple LLVM version 9.0.0 (clang-900.0.39.2)
Target: x86_64-apple-darwin17.4.0
Thread model: posix
InstalledDir: /Library/Developer/CommandLineTools/usr/bin