gcc -c   -s -O2 -DWIN32 -DWIN64 -DCONSERVATIVE -DPERL_TEXTMODE_SCRIPTS -DPERL_IMPLICIT_CONTEXT -DPERL_IMPLICIT_SYS -DUSE_PERLIO -D__USE_MINGW_ANSI_STDIO -fwrapv -fno-strict-aliasing -mms-bitfields -s -O2   -DVERSION=\"1.52\" -DXS_VERSION=\"1.52\"  "-IC:\_64\perl530_810\lib\CORE"  -DPERL_EXT -DUSE_PPPORT_H "-DMY_FORMAT=\"%.17\"" ListUtil.c

##</code><code>##

printf("\n**%s**\n", MY_FORMAT);

##</code><code>##

use strict;
use warnings;
use Config;

use Inline C => Config =>
  USING => 'ParseRegExp',
  CCFLAGSEX => q["-DMY_FORMAT=\"%.16e\""],
  BUILD_NOISY => 1,
;

use Inline C =><<'EOC';

SV * foo(void) {
  printf(MY_FORMAT, sqrt(2.0));
  printf("\n");
}

EOC

foo();

##</code><code>##

gcc -c  -iquote"C:/_32/C" -s -O2 -DWIN32 -DWIN64 -DCONSERVATIVE  -DPERL_TEXTMODE_SCRIPTS -DPERL_IMPLICIT_CONTEXT -DPERL_IMPLICIT_SYS -DUSE_PERLIO -D__USE_MINGW_ANSI_STDIO -fwrapv -fno-strict-aliasing -mms-bitfields "-DMY_FORMAT=\"%.16e\"" -s -O2   -DVERSION=\"0.00\" -DXS_VERSION=\"0.00\"  "-IC:\_64\perl530_810\lib\CORE"   try_pl_d937.c
<command-line>: warning: missing terminating " character
try_pl_d937.xs:1:10: fatal error: EXTERN.h: No such file or directory
 #include "EXTERN.h"
          ^~~~~~~~~~
compilation terminated.