Seems I wasn't clear enough:

This is *one* MSYS2 system (on a 64bit machine), with the packages for both the toolchains for mingw32 and mingw64 installed.
The only difference between using it to compile MinGW 64bit or 32bit executables is the environment setting. (In the similar fashion as on the Windows command shell, where the difference between using VisualStudio 32bit and 64bit compilers is the environment setting achieved by running vsvarsall.bat.)

Perl is running on MSYS2.

$ perl -V
Summary of my perl5 (revision 5 version 28 subversion 2) configuration:

  Platform:
    osname=msys
    osvers=3.0.6(0.33853)
    archname=x86_64-msys-thread-multi
    uname='msys_nt-6.1 warlock 3.0.6(0.33853) 2019-04-15 06:44 x86_64 msys '
    config_args='-des -Dusethreads -Doptimize=-march=x86-64 -mtune=generic -O2 -pipe -Dprefix=/usr -Dvendorprefix=/usr -Dprivlib=/usr/share/perl5/core_perl -Darchlib=/usr/lib/perl5/core_perl -Dsitelib=/usr/share/perl5/site_perl -Dsitearch=/usr/lib/perl5/site_perl -Dvendorlib=/usr/share/perl5/vendor_perl -Dvendorarch=/usr/lib/perl5/vendor_perl -Dscriptdir=/usr/bin/core_perl -Dsitescript=/usr/bin/site_perl -Dvendorscript=/usr/bin/vendor_perl -Dinc_version_list=none -Dman1ext=1perl -Dman3ext=3perl -Darchname=-msys-threads -Dmyarchname=-msys -Dlibperl=msys-perl5_28.dll -Dcc=gcc -Dld=g++ -Accflags=-march=x86-64 -mtune=generic -O2 -pipe -fwrapv'
    hint=recommended
    useposix=true
    d_sigaction=define
    useithreads=define
    usemultiplicity=define
    use64bitint=define
    use64bitall=define
    uselongdouble=undef
    usemymalloc=n
    default_inc_excludes_dot=define
    bincompat5005=undef
  Compiler:
    cc='gcc'
    ccflags ='-DPERL_USE_SAFE_PUTENV -U__STRICT_ANSI__ -D_GNU_SOURCE -march=x86-64 -mtune=generic -O2 -pipe -fwrapv -fno-strict-aliasing -fstack-protector-strong'
    optimize='-march=x86-64 -mtune=generic -O2 -pipe'
    cppflags='-DPERL_USE_SAFE_PUTENV -U__STRICT_ANSI__ -D_GNU_SOURCE -march=x86-64 -mtune=generic -O2 -pipe -fwrapv -fno-strict-aliasing -fstack-protector-strong'
    ccversion=''
    gccversion='7.4.0'
    gccosandvers=''
    intsize=4
    longsize=8
    ptrsize=8
    doublesize=8
    byteorder=12345678
    doublekind=3
    d_longlong=define
    longlongsize=8
    d_longdbl=define
    longdblsize=16
    longdblkind=3
    ivtype='long'
    ivsize=8
    nvtype='double'
    nvsize=8
    Off_t='off_t'
    lseeksize=8
    alignbytes=8
    prototype=define
  Linker and Libraries:
    ld='g++'
    ldflags =' -Wl,--enable-auto-import -Wl,--export-all-symbols -Wl,--enable-auto-image-base -fstack-protector-strong'
    libpth=/usr/lib
    libs=-lpthread -lgdbm -ldb -ldl -lcrypt -lgdbm_compat
    perllibs=-lpthread -ldl -lcrypt
    libc=/usr/lib/libmsys-2.0.a
    so=dll
    useshrplib=true
    libperl=msys-perl5_28.dll
    gnulibc_version=''
  Dynamic Linking:
    dlsrc=dl_dlopen.xs
    dlext=dll
    d_dlsymun=undef
    ccdlflags=' '
    cccdlflags=' '
    lddlflags=' --shared  -Wl,--enable-auto-import -Wl,--export-all-symbols -Wl,--enable-auto-image-base -fstack-protector-strong'


Characteristics of this binary (from libperl):
  Compile-time options:
    HAS_TIMES
    MULTIPLICITY
    PERLIO_LAYERS
    PERL_COPY_ON_WRITE
    PERL_DONT_CREATE_GVSV
    PERL_IMPLICIT_CONTEXT
    PERL_OP_PARENT
    PERL_PRESERVE_IVUV
    PERL_USE_SAFE_PUTENV
    USE_64_BIT_ALL
    USE_64_BIT_INT
    USE_ITHREADS
    USE_LARGE_FILES
    USE_LOCALE
    USE_LOCALE_COLLATE
    USE_LOCALE_CTYPE
    USE_LOCALE_NUMERIC
    USE_LOCALE_TIME
    USE_PERLIO
    USE_PERL_ATOF
    USE_REENTRANT_API
  Built under msys
  Compiled at Apr 25 2019 07:29:36
  @INC:
    /usr/lib/perl5/site_perl
    /usr/share/perl5/site_perl
    /usr/lib/perl5/vendor_perl
    /usr/share/perl5/vendor_perl
    /usr/lib/perl5/core_perl
    /usr/share/perl5/core_perl