well, didn't work out, but at least now I've ruled out Win32::API/Win32::Console , though it probably is -static-libgcc AND -static-libstdc++ related

$ perl -MLWP::UserAgent -e " LWP::UserAgent->new->env_proxy "
The locale codeset (cp437) isn't one that perl can decode, stopped at 
+C:/perl/site/5.14.1/lib/Encode/Locale.pm line 87.
Compilation failed in require at C:/perl/site/5.14.1/lib/LWP/UserAgent
+.pm line 976.

$ perl -MEncode::Locale -MLWP::UserAgent -e " LWP::UserAgent->new->env
+_proxy "

$ perl -d:Modlist -MEncode::Locale -MLWP::UserAgent -e " LWP::UserAgen
+t->new->env_proxy "
Carp                   1.20
Config
Encode                 2.43
Encode::Alias          2.14
Encode::Byte           2.04
Encode::Config         2.05
Encode::Encoding       2.05
Encode::Locale         1.02
Exporter             5.64_03
Exporter::Heavy      5.64_03
Fcntl                  1.11
HTTP::Config           6.00
HTTP::Date             6.00
HTTP::Headers          6.00
HTTP::Message          6.02
HTTP::Request          6.00
HTTP::Response         6.01
HTTP::Status           6.00
LWP                    6.02
LWP::MemberMixin
LWP::Protocol          6.00
LWP::UserAgent         6.02
Storable               2.30
Time::Local          1.2000
URI                    1.58
URI::Escape            3.30
XSLoader               0.15
base                   2.16
bytes                  1.04
constant               1.21
overload               1.13
vars                   1.02
warnings               1.12
warnings::register     1.02


$ perl -V
Summary of my perl5 (revision 5 version 14 subversion 1) configuration
+:
  Commit id: cc92ef02098c000d945bcf93c92bdb2a0a05fa97
  Platform:
    osname=MSWin32, osvers=5.1, archname=MSWin32-x86-multi-thread
    uname=''
    config_args='undef'
    hint=recommended, useposix=true, d_sigaction=undef
    useithreads=define, usemultiplicity=define
    useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=und
+ef
    use64bitint=undef, use64bitall=undef, uselongdouble=undef
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='gcc', ccflags =' -s -O2 -DWIN32  -DPERL_TEXTMODE_SCRIPTS -DPER
+L_IMPLICIT_CONTEXT -DPERL_IMPLICIT_SYS -fno-strict-aliasing -mms-bitf
+ields',
    optimize='-s -O2',
    cppflags='-DWIN32'
    ccversion='', gccversion='4.5.2', gccosandvers=''
    intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
    d_longlong=undef, longlongsize=8, d_longdbl=define, longdblsize=12
    ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='long lo
+ng', lseeksize=8
    alignbytes=8, prototype=define
  Linker and Libraries:
    ld='g++', ldflags ='-static-libgcc -static-libstdc++  -s -L"c:\per
+l\5.14.1\lib\MSWin32-x86-multi-thread\CORE" -L"C:\MinGW\lib"'
    libpth=C:\MinGW\lib
    libs=-lmoldname -lkernel32 -luser32 -lgdi32 -lwinspool -lcomdlg32 
+-ladvapi32 -lshell32 -lole32 -loleaut32 -lnetapi32 -luuid -lws2_32 -l
+mpr -lwinmm -lversion -lodbc32 -lodbccp32 -lcomctl32
    perllibs=-lmoldname -lkernel32 -luser32 -lgdi32 -lwinspool -lcomdl
+g32 -ladvapi32 -lshell32 -lole32 -loleaut32 -lnetapi32 -luuid -lws2_3
+2 -lmpr -lwinmm -lversion -lodbc32 -lodbccp32 -lcomctl32
    libc=, so=dll, useshrplib=true, libperl=libperl514.a
    gnulibc_version=''
  Dynamic Linking:
    dlsrc=dl_win32.xs, dlext=dll, d_dlsymun=undef, ccdlflags=' '
    cccdlflags=' ', lddlflags='-mdll -static-libgcc -static-libstdc++ 
+ -s -L"c:\perl\5.14.1\lib\MSWin32-x86-multi-thread\CORE" -L"C:\MinGW\
+lib"'


Characteristics of this binary (from libperl):
  Compile-time options: MULTIPLICITY PERL_DONT_CREATE_GVSV
                        PERL_IMPLICIT_CONTEXT PERL_IMPLICIT_SYS
                        PERL_MALLOC_WRAP PERL_PRESERVE_IVUV PL_OP_SLAB
+_ALLOC
                        USE_ITHREADS USE_LARGE_FILES USE_PERLIO
                        USE_PERL_ATOF
  Built under MSWin32
  Compiled at Jul 22 2011 00:38:35
  @INC:
    C:/perl/site/5.14.1/lib/MSWin32-x86-multi-thread
    C:/perl/site/5.14.1/lib
    C:/perl/5.14.1/lib/MSWin32-x86-multi-thread
    C:/perl/5.14.1/lib
    .
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