if (not -f ($perl_h = $self->catfile($self->{PERL_INC},"perl.h"))
to
if(0)
[download]

>perl -V

Summary of my perl5 (revision 5 version 30 subversion 0) configuration
+:

  Platform:
    osname=MSWin32
    osvers=10.0.17763.529
    archname=MSWin32-x86-multi-thread-64int
    uname='Win32 strawberry-perl 5.30.0.1 #1 Thu May 23 09:43:53 2019 
+i386'
    config_args='undef'
    hint=recommended
    useposix=true
    d_sigaction=undef
    useithreads=define
    usemultiplicity=define
    use64bitint=define
    use64bitall=undef
    uselongdouble=undef
    usemymalloc=n
    default_inc_excludes_dot=define
    bincompat5005=undef
  Compiler:
    cc='gcc'
    ccflags =' -s -O2 -DWIN32 -D__USE_MINGW_ANSI_STDIO -DPERL_TEXTMODE
+_SCRIPTS -DPERL_IMPLICIT_CONTEXT -DPERL_IMPLICIT_SYS -DUSE_PERLIO -fw
+rapv -fno-strict-aliasing -mms-bitfields'
    optimize='-s -O2'
    cppflags='-DWIN32'
    ccversion=''
    gccversion='8.3.0'
    gccosandvers=''
    intsize=4
    longsize=4
    ptrsize=4
    doublesize=8
    byteorder=12345678
    doublekind=3
    d_longlong=define
    longlongsize=8
    d_longdbl=define
    longdblsize=12
    longdblkind=3
    ivtype='long long'
    ivsize=8
    nvtype='double'
    nvsize=8
    Off_t='long long'
    lseeksize=8
    alignbytes=8
    prototype=define
  Linker and Libraries:
    ld='g++'
    ldflags ='-s -L"D:\STRAWB~1\perl\lib\CORE" -L"D:\STRAWB~1\c\lib"'
    libpth=D:\STRAWB~1\c\lib D:\STRAWB~1\c\i686-w64-mingw32\lib D:\STR
+AWB~1\c\lib\gcc\i686-w64-mingw32\8.3.0
    libs= -lmoldname -lkernel32 -luser32 -lgdi32 -lwinspool -lcomdlg32
+ -ladvapi32 -lshell32 -lole32 -loleaut32 -lnetapi32 -luuid -lws2_32 -
+lmpr -lwinmm -lversion -lodbc32 -lodbccp32 -lcomctl32
    perllibs= -lmoldname -lkernel32 -luser32 -lgdi32 -lwinspool -lcomd
+lg32 -ladvapi32 -lshell32 -lole32 -loleaut32 -lnetapi32 -luuid -lws2_
+32 -lmpr -lwinmm -lversion -lodbc32 -lodbccp32 -lcomctl32
    libc=
    so=dll
    useshrplib=true
    libperl=libperl530.a
    gnulibc_version=''
  Dynamic Linking:
    dlsrc=dl_win32.xs
    dlext=xs.dll
    d_dlsymun=undef
    ccdlflags=' '
    cccdlflags=' '
    lddlflags='-mdll -s -L"D:\STRAWB~1\perl\lib\CORE" -L"D:\STRAWB~1\c
+\lib"'


Characteristics of this binary (from libperl):
  Compile-time options:
    HAS_TIMES
    HAVE_INTERP_INTERN
    MULTIPLICITY
    PERLIO_LAYERS
    PERL_COPY_ON_WRITE
    PERL_DONT_CREATE_GVSV
    PERL_IMPLICIT_CONTEXT
    PERL_IMPLICIT_SYS
    PERL_MALLOC_WRAP
    PERL_OP_PARENT
    PERL_PRESERVE_IVUV
    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
  Built under MSWin32
  Compiled at May 23 2019 09:49:35
  @INC:
    D:/Strawberry/perl/site/lib
    D:/Strawberry/perl/vendor/lib
    D:/Strawberry/perl/lib
[download]

=================================================

>perl -MExtUtils::MakeMaker -le "print $ExtUtils::MakeMaker::VERSION;" 7.36

I still can't reproduce the problem that you're experiencing.
Using the same build of Strawberry Perl as you:

C:\sisyphusion\Encode-IBM-0.11>perl -V
Summary of my perl5 (revision 5 version 30 subversion 0) configuration
+:

  Platform:
    osname=MSWin32
    osvers=10.0.17763.529
    archname=MSWin32-x86-multi-thread-64int
    uname='Win32 strawberry-perl 5.30.0.1 #1 Thu May 23 09:43:53 2019 
+i386'
    .................
[download]

I find no problem if Makefile.PL has been modified as I specified earlier:

C:\sisyphusion\Encode-IBM-0.11>perl Makefile.PL
enc2xs is C:\_64\strawberry-vanilla-5.30.0\perl\bin\enc2xs.bat
encode.h is at C:\_32\strawberry-5.30.0\perl\lib\Encode
Checking if your kit is complete...
Looks good
Generating a gmake-style Makefile
Writing Makefile for Encode::IBM
Writing MYMETA.yml and MYMETA.json

C:\sisyphusion\Encode-IBM-0.11>gmake test
Running Mkbootstrap for IBM ()
"C:\_32\strawberry-5.30.0\perl\bin\perl.exe" -MExtUtils::Command -e ch
+mod -- 644
 "IBM.bs"
"C:\_32\strawberry-5.30.0\perl\bin\perl.exe" -MExtUtils::Command::MM -
+e cp_nonempty -- IBM.bs blib\arch\auto\Encode\IBM\IBM.bs 644
"C:\_32\strawberry-5.30.0\perl\bin\perl.exe"  C:\_64\strawberry-vanill
+a-5.30.0\perl\bin\enc2xs.bat -"Q" -o IBM_937_t.c -f IBM_937_t.fnm
Reading ibm-937 (ibm-937)
"C:\_32\strawberry-5.30.0\perl\bin\perl.exe"  C:\_64\strawberry-vanill
+a-5.30.0\perl\bin\enc2xs.bat -"Q" -o IBM_964_t.c -f IBM_964_t.fnm
Reading ibm-964 (ibm-964)
"C:\_32\strawberry-5.30.0\perl\bin\perl.exe"  C:\_64\strawberry-vanill
+a-5.30.0\perl\bin\enc2xs.bat -"Q" -o IBM_835_t.c -f IBM_835_t.fnm
Reading ibm-835 (ibm-835)
"C:\_32\strawberry-5.30.0\perl\bin\perl.exe"  C:\_64\strawberry-vanill
+a-5.30.0\perl\bin\enc2xs.bat -"Q" -o IBM_939_t.c -f IBM_939_t.fnm
Reading ibm-939 (ibm-939)
"C:\_32\strawberry-5.30.0\perl\bin\perl.exe"  C:\_64\strawberry-vanill
+a-5.30.0\perl\bin\enc2xs.bat -"Q" -o IBM_947_t.c -f IBM_947_t.fnm
Reading ibm-947 (ibm-947)
"C:\_32\strawberry-5.30.0\perl\bin\perl.exe" "C:\_32\strawberry-5.30.0
+\perl\lib\ExtUtils/xsubpp"  -nolinenumbers -typemap C:\_32\strawberry
+-5.30.0\perl\lib\ExtUtils\typemap  IBM.xs > IBM.xsc
"C:\_32\strawberry-5.30.0\perl\bin\perl.exe" -MExtUtils::Command -e mv
+ -- IBM.xsc IBM.c
gcc -c  -IC:\_32\strawberry-5.30.0\perl\lib\Encode -s -O2 -DWIN32 -D__
+USE_MINGW_ANSI_STDIO -DPERL_TEXTMODE_SCRIPTS -DPERL_IMPLICIT_CONTEXT 
+-DPERL_IMPLICIT_SYS -DUSE_PERLIO -fwrapv -fno-strict-aliasing -mms-bi
+tfields -s -O2   -DVERSION=\"0.11\" -DXS_VERSION=\"0.11\"  "-IC:\_32\
+strawberry-5.30.0\perl\lib\CORE"   IBM.c
gcc -c  -IC:\_32\strawberry-5.30.0\perl\lib\Encode -s -O2 -DWIN32 -D__
+USE_MINGW_ANSI_STDIO -DPERL_TEXTMODE_SCRIPTS -DPERL_IMPLICIT_CONTEXT 
+-DPERL_IMPLICIT_SYS -DUSE_PERLIO -fwrapv -fno-strict-aliasing -mms-bi
+tfields -s -O2   -DVERSION=\"0.11\" -DXS_VERSION=\"0.11\"  "-IC:\_32\
+strawberry-5.30.0\perl\lib\CORE"   IBM_835_
t.c
gcc -c  -IC:\_32\strawberry-5.30.0\perl\lib\Encode -s -O2 -DWIN32 -D__
+USE_MINGW_ANSI_STDIO -DPERL_TEXTMODE_SCRIPTS -DPERL_IMPLICIT_CONTEXT 
+-DPERL_IMPLICIT_SYS -DUSE_PERLIO -fwrapv -fno-strict-aliasing -mms-bi
+tfields -s -O2   -DVERSION=\"0.11\" -DXS_VERSION=\"0.11\"  "-IC:\_32\
+strawberry-5.30.0\perl\lib\CORE"   IBM_937_t.c
gcc -c  -IC:\_32\strawberry-5.30.0\perl\lib\Encode -s -O2 -DWIN32 -D__
+USE_MINGW_ANSI_STDIO -DPERL_TEXTMODE_SCRIPTS -DPERL_IMPLICIT_CONTEXT 
+-DPERL_IMPLICIT_SYS -DUSE_PERLIO -fwrapv -fno-strict-aliasing -mms-bi
+tfields -s -O2   -DVERSION=\"0.11\" -DXS_VERSION=\"0.11\"  "-IC:\_32\
+strawberry-5.30.0\perl\lib\CORE"   IBM_939_t.c
gcc -c  -IC:\_32\strawberry-5.30.0\perl\lib\Encode -s -O2 -DWIN32 -D__
+USE_MINGW_ANSI_STDIO -DPERL_TEXTMODE_SCRIPTS -DPERL_IMPLICIT_CONTEXT 
+-DPERL_IMPLICIT_SYS -DUSE_PERLIO -fwrapv -fno-strict-aliasing -mms-bi
+tfields -s -O2   -DVERSION=\"0.11\" -DXS_VERSION=\"0.11\"  "-IC:\_32\
+strawberry-5.30.0\perl\lib\CORE"   IBM_947_t.c
gcc -c  -IC:\_32\strawberry-5.30.0\perl\lib\Encode -s -O2 -DWIN32 -D__
+USE_MINGW_ANSI_STDIO -DPERL_TEXTMODE_SCRIPTS -DPERL_IMPLICIT_CONTEXT 
+-DPERL_IMPLICIT_SYS -DUSE_PERLIO -fwrapv -fno-strict-aliasing -mms-bi
+tfields -s -O2   -DVERSION=\"0.11\" -DXS_VERSION=\"0.11\"  "-IC:\_32\
+strawberry-5.30.0\perl\lib\CORE"   IBM_964_t.c
"C:\_32\strawberry-5.30.0\perl\bin\perl.exe" -MExtUtils::Mksymlists \ 
+    -e "Mksymlists('NAME'=>\"Encode::IBM\", 'DLBASE' => 'IBM', 'DL_FU
+NCS' => { }, 'FUNCLIST' => [], 'IMPORTS' => {  }, 'DL_VARS' => []);"
g++.exe IBM.def -o blib\arch\auto\Encode\IBM\IBM.xs.dll -mdll -s -L"C:
+\_32\strawberry-5.30.0\perl\lib\CORE" -L"C:\_32\strawberry-5.30.0\c\l
+ib" IBM.o IBM_835_t.o IBM_937_t.o IBM_939_t.o IBM_947_t.o IBM_964_t.o
+   "C:\_32\strawberry-5.30.0\perl\lib\CORE\libperl530.a" -lmoldname -
+lkernel32 -luser32 -lgdi32 -lwinspool -lcomdlg32 -ladvapi32 -lshell32
+ -lole32 -loleaut32 -lnetapi32 -luuid -lws2_32 -lmpr -lwinmm -lversio
+n -lodbc32 -lodbccp32 -lcomctl32 -Wl,--enable-auto-image-base "C:\_32
+\strawberry-5.30.0\perl\bin\perl.exe" -MExtUtils::Command -e chmod --
+ 755 blib\arch\auto\Encode\IBM\IBM.xs.dll
cp lib/Encode/IBM.pm blib\lib\Encode\IBM.pm
cp lib/Encode/IBM/835SOSI.pm blib\lib\Encode\IBM\835SOSI.pm
cp lib/Encode/IBM/939SOSI.pm blib\lib\Encode\IBM\939SOSI.pm
cp lib/Encode/IBM/835SOSI/TSGH.pm blib\lib\Encode\IBM\835SOSI\TSGH.pm
cp lib/Encode/IBM/947SOSI.pm blib\lib\Encode\IBM\947SOSI.pm
"C:\_32\strawberry-5.30.0\perl\bin\perl.exe" "-MExtUtils::Command::MM"
+ "-MTest::
Harness" "-e" "undef *Test::Harness::Switches; test_harness(0, 'blib\l
+ib', 'blib
\arch')" t/*.t
t/IBM.t .. ok
All tests successful.
Files=1, Tests=3,  1 wallclock secs ( 0.03 usr +  0.00 sys =  0.03 CPU
+)
Result: PASS

C:\sisyphusion\Encode-IBM-0.11>gmake install
"C:\_32\strawberry-5.30.0\perl\bin\perl.exe" -MExtUtils::Command::MM -
+e cp_nonem
pty -- IBM.bs blib\arch\auto\Encode\IBM\IBM.bs 644
Files found in blib\arch: installing files in blib\lib into architectu
+re depende
nt library tree
Installing C:\_32\strawberry-5.30.0\perl\site\lib\auto\Encode\IBM\IBM.
+xs.dll
Appending installation info to C:\_32\strawberry-5.30.0\perl\lib/perll
+ocal.pod
 require Encode::IBM;
 require Encode::IBM::835SOSI;
 require Encode::IBM::939SOSI;
 require Encode::IBM::947SOSI;
 require Encode::IBM::835SOSI::TSGH;
 require Encode;
 require Encode::compat;
 require Encode::Locale;
 require Encode::compat::5006001;
 require Encode::compat::Alias;
Constant subroutine Encode::FB_PERLQQ redefined at C:/_64/strawberry-v
+anilla-5.3
0.0/perl/lib/constant.pm line 171.
Constant subroutine Encode::FB_HTMLCREF redefined at C:/_64/strawberry
+-vanilla-5
.30.0/perl/lib/constant.pm line 171.
Constant subroutine Encode::FB_XMLCREF redefined at C:/_64/strawberry-
+vanilla-5.
30.0/perl/lib/constant.pm line 171.
Prototype mismatch: sub Encode::find_encoding ($;$) vs none at C:/_64/
+strawberry
-vanilla-5.30.0/perl/vendor/lib/Encode/compat/common.pm line 80.
Prototype mismatch: sub Encode::encode_utf8 ($) vs ($;$) at C:/_64/str
+awberry-va
nilla-5.30.0/perl/vendor/lib/Encode/compat/common.pm line 88.
 require Encode::compat::common;
 require Encode;
 require Encode::Alias;
 require Encode::Byte;
 require Encode::CJKConstants;
 require Encode::CN;
 require Encode::Config;
 require Encode::ConfigLocal;
 require Encode::EBCDIC;
 require Encode::Encoder;
 require Encode::Encoding;
 require Encode::GSM0338;
 require Encode::Guess;
 require Encode::JP;
 require Encode::KR;
 require Encode::Symbol;
 require Encode::TW;
 require Encode::Unicode;
 require Encode::CN::HZ;
 require Encode::JP::H2Z;
 require Encode::JP::JIS7;
 require Encode::KR::2022_KR;
 require Encode::MIME::Header;
 require Encode::MIME::Name;
 require Encode::MIME::Header::ISO_2022_JP;
 require Encode::Unicode::UTF7;
$Encode::ExtModule{'ibm-835'} = "Encode::IBM";
$Encode::ExtModule{'ibm-835-sosi'} = "Encode::IBM";
$Encode::ExtModule{'ibm-835-sosi-tsgh'} = "Encode::IBM";
$Encode::ExtModule{'ibm-937'} = "Encode::IBM";
$Encode::ExtModule{'ibm-939'} = "Encode::IBM";
$Encode::ExtModule{'ibm-939-sosi'} = "Encode::IBM";
$Encode::ExtModule{'ibm-947'} = "Encode::IBM";
$Encode::ExtModule{'ibm-947-sosi'} = "Encode::IBM";
$Encode::ExtModule{'ibm-964'} = "Encode::IBM";
C:/_64/strawberry-vanilla-5.30.0/perl/lib/Encode
Generating C:\_64\strawberry-vanilla-5.30.0\perl\lib\Encode\ConfigLoca
+l.pm...

C:\sisyphusion\Encode-IBM-0.11>
[download]

I don't think I can help further until I see the outputs of both:

type Makefile.PL
amd
set PATH
[download]

Cheers,
Rob

... In strawberry/perl/lib/ExtUtils/MM_Unix.pm, try changing the line:

Hi

How about no?

https://metacpan.org/source/AUDREYT/Encode-IBM-0.11/Makefile.PL is a 2008 file generated by enc2xs

Latest version of enc2xs is from 13 Mar 2019

Run latest enc2xs/makemaker then see whats what

Run latest enc2xs/makemaker then see whats what

Yeah - the OP could give that a go.
What does it involve exactly ? That is, what's the exact command that gets run, and from which directory does one need to run it ?

The oldest Windows perl I have is perl-5.8.8 (enc2xs-2.01) and it's building Encode-IBM-0.11 just fine apart from a million or so warnings about:

attention : initialization discards 'const' qualifier from pointer tar
+get type [enabled by default]"
[download]

But the build succeeds, and the test suite passes ... and no bizarre warnings produced during the 'perl Makefile.PL' step.

The oldest Strawberry Perl I have is perl-5.12.2 (enc2xs-2.07) which also builds Encode-IBM-0.11 just fine (and no warnings).
Strawberry Perl 5.30.0 has enc2xs-2.21.
According to the note at the beginning of the Makefile.PL (which I hadn't noticed), it was generated using enc2xs-2.05.

Cheers,
Rob

Failed to opendir 'D:\STRAWB~1\perl\lib\CORE' to find header files: No
+ such file or directory at D:/Strawberry/perl/lib/ExtUtils/MM_Any.pm 
+line 3049.
[download]

opendir my $dh, $header_dir or die "Failed to opendir '$header_dir' to
+ find header files: $!";
[download]

C:\>perl -le "opendir my $dh, 'C:\strawberry\perl\lib\CORE' or die $!;
+"

C:\>perl -le "opendir my $dh, 'C:\strawb~1\perl\lib\CORE' or die $!;"

C:\>perl -le "opendir my $dh, 'C:\STRAWB~1\perl\lib\CORE' or die $!;"

C:\>
[download]

Thanks, Perl was OK after I have reinstalled my Strawberry from scratch... However - the workaround still fails, now in a later stage.

D:\perl64\cpan\sources\modules\encode-3.01\Encode-3.01>gmake install
gmake[1]: Entering directory 'D:/perl64/cpan/sources/modules/encode-3.
+01/Encode-3.01/Byte'
"D:\Strawberry\perl\bin\perl.exe" -MExtUtils::Command::MM -e cp_nonemp
+ty -- Byte.bs ..\blib\arch\auto\Encode\Byte\Byte.bs 644
gmake[1]: Leaving directory 'D:/perl64/cpan/sources/modules/encode-3.0
+1/Encode-3.01/Byte'
gmake[1]: Entering directory 'D:/perl64/cpan/sources/modules/encode-3.
+01/Encode-3.01/CN'
"D:\Strawberry\perl\bin\perl.exe" -MExtUtils::Command::MM -e cp_nonemp
+ty -- CN.bs ..\blib\arch\auto\Encode\CN\CN.bs 644
gmake[1]: Leaving directory 'D:/perl64/cpan/sources/modules/encode-3.0
+1/Encode-3.01/CN'
gmake[1]: Entering directory 'D:/perl64/cpan/sources/modules/encode-3.
+01/Encode-3.01/EBCDIC'
"D:\Strawberry\perl\bin\perl.exe" -MExtUtils::Command::MM -e cp_nonemp
+ty -- EBCDIC.bs ..\blib\arch\auto\Encode\EBCDIC\EBCDIC.bs 644
gmake[1]: Leaving directory 'D:/perl64/cpan/sources/modules/encode-3.0
+1/Encode-3.01/EBCDIC'
gmake[1]: Entering directory 'D:/perl64/cpan/sources/modules/encode-3.
+01/Encode-3.01/JP'
"D:\Strawberry\perl\bin\perl.exe" -MExtUtils::Command::MM -e cp_nonemp
+ty -- JP.bs ..\blib\arch\auto\Encode\JP\JP.bs 644
gmake[1]: Leaving directory 'D:/perl64/cpan/sources/modules/encode-3.0
+1/Encode-3.01/JP'
gmake[1]: Entering directory 'D:/perl64/cpan/sources/modules/encode-3.
+01/Encode-3.01/KR'
"D:\Strawberry\perl\bin\perl.exe" -MExtUtils::Command::MM -e cp_nonemp
+ty -- KR.bs ..\blib\arch\auto\Encode\KR\KR.bs 644
gmake[1]: Leaving directory 'D:/perl64/cpan/sources/modules/encode-3.0
+1/Encode-3.01/KR'
gmake[1]: Entering directory 'D:/perl64/cpan/sources/modules/encode-3.
+01/Encode-3.01/Symbol'
"D:\Strawberry\perl\bin\perl.exe" -MExtUtils::Command::MM -e cp_nonemp
+ty -- Symbol.bs ..\blib\arch\auto\Encode\Symbol\Symbol.bs 644
gmake[1]: Leaving directory 'D:/perl64/cpan/sources/modules/encode-3.0
+1/Encode-3.01/Symbol'
gmake[1]: Entering directory 'D:/perl64/cpan/sources/modules/encode-3.
+01/Encode-3.01/TW'
"D:\Strawberry\perl\bin\perl.exe" -MExtUtils::Command::MM -e cp_nonemp
+ty -- TW.bs ..\blib\arch\auto\Encode\TW\TW.bs 644
gmake[1]: Leaving directory 'D:/perl64/cpan/sources/modules/encode-3.0
+1/Encode-3.01/TW'
gmake[1]: Entering directory 'D:/perl64/cpan/sources/modules/encode-3.
+01/Encode-3.01/Unicode'
"D:\Strawberry\perl\bin\perl.exe" -MExtUtils::Command::MM -e cp_nonemp
+ty -- Unicode.bs ..\blib\arch\auto\Encode\Unicode\Unicode.bs 644
g++ Unicode.def -o ..\blib\arch\auto\Encode\Unicode\Unicode.xs.dll -md
+ll -s -L"D:\Strawberry\perl\lib\CORE" -L"D:\Strawberry\c\lib" Unicode
+.o   "D:\Strawberry\perl\lib\CORE\libperl530.a" -lmoldname -lkernel32
+ -luser32 -lgdi32 -lwinspool -lcomdlg32 -ladvapi32 -lshell32 -lole32 
+-loleaut32 -lnetapi32 -luuid -lws2_32 -lmpr -lwinmm -lversion -lodbc3
+2 -lodbccp32 -lcomctl32 -Wl,--enable-auto-image-base
g++: error: Unicode.o: No such file or directory
gmake[1]: *** [Makefile:454: ..\blib\arch\auto\Encode\Unicode\Unicode.
+xs.dll] Error 1
gmake[1]: Leaving directory 'D:/perl64/cpan/sources/modules/encode-3.0
+1/Encode-3.01/Unicode'
gmake: *** [Makefile:604: subdirs] Error 2
[download]

g++: error: Unicode.o: No such file or directory

I don't know how that error arises.
Encode-3.01 builds and tests fine for me on both 32-bit and 64-bit Strawberry Perl 5.30.0.
Also, you should already have Encode-3.01 installed (in perl\vendor\lib), and there is no point installing something you already have:

C:\>perl -MEncode -le "print $Encode::VERSION;"
3.01
[download]

Cheers,
Rob