Avoid ODR violation, consistently define ZLIB_CONST

At least my --enable-lto --enable-mergelibs build diagnosed

> [build LNK] Library/libmergedlo.so
> workdir/UnpackedTarball/zlib/zlib.h:86:16: warning: type ‘struct z_stream_s’ violates the C++ One Definition Rule [-Wodr]
>    86 | typedef struct z_stream_s {
>       |                ^
> workdir/UnpackedTarball/zlib/zlib.h:86: note: a different type is defined in another translation unit
>    86 | typedef struct z_stream_s {
>       |
> workdir/UnpackedTarball/zlib/zlib.h:87:20: note: the first difference of corresponding definitions is field ‘next_in’
>    87 |     z_const Bytef *next_in;     /* next input byte */
>       |                    ^
> workdir/UnpackedTarball/zlib/zlib.h:87: note: a field of same name but different type is defined in another translation unit
>    87 |     z_const Bytef *next_in;     /* next input byte */
>       |

(And ZLIB_CONST then required a small adaption in
tools/source/zcodec/zcodec.cxx, plus some loplugin:redundantcast.  And
gb_PrecompiledHeader_ignore_flags_system had to be updated to avoid errors like

> Error reusing pch/inc/pch/precompiled_system by Library_wpftdraw.
>  precompiled header flags : -DBOOST_ALL_NO_LIB -DBOOST_ERROR_CODE_HEADER_ONLY -DBOOST_MEM_FN_ENABLE_CDECL -DBOOST_OPTIONAL_USE_OLD_DEFINITION_OF_NONE -DBOOST_SYSTEM_NO_DEPRECATED -DCPPU_ENV=msci -DDBG_UTIL -DEXCEPTIONS_ON -DINTEL -DNOMINMAX -DOSL_DEBUG_LEVEL=1 -DPCH_LEVEL=4 -DSAL_LOG_INFO -DSAL_LOG_WARN -DWIN32 -DWNT -D_CRT_NONSTDC_NO_DEPRECATE -D_CRT_NON_CONFORMING_SWPRINTFS -D_CRT_SECURE_NO_DEPRECATE -D_DEBUG -D_DLL -D_HAS_AUTO_PTR_ETC -D_MT -D_REENTRANT -D_SCL_SECURE_NO_WARNINGS -D_SILENCE_CXX17_CODECVT_HEADER_DEPRECATION_WARNING -D_SILENCE_CXX17_OLD_ALLOCATOR_MEMBERS_DEPRECATION_WARNING -D_SILENCE_CXX17_RESULT_OF_DEPRECATION_WARNING -D_WIN32_WINNT=0x0601 -D_X86_=1 -EHs -GR -GS -Gd -Gs -Gy -MDd -Od -W4 -Wv:18 -Zc:__cplusplus -Zm500 -bigobj -nologo -permissive- -std:c++17 -utf-8 -wd4127 -wd4201 -wd4244 -wd4250 -wd4251 -wd4267 -wd4275 -wd4505 -wd4611 -wd4706
>             object flags  : -DBOOST_ALL_NO_LIB -DBOOST_ERROR_CODE_HEADER_ONLY -DBOOST_MEM_FN_ENABLE_CDECL -DBOOST_OPTIONAL_USE_OLD_DEFINITION_OF_NONE -DBOOST_SYSTEM_NO_DEPRECATED -DCPPU_ENV=msci -DDBG_UTIL -DEXCEPTIONS_ON -DINTEL -DNOMINMAX -DOSL_DEBUG_LEVEL=1 -DPCH_LEVEL=4 -DSAL_LOG_INFO -DSAL_LOG_WARN -DWIN32 -DWNT -DZLIB_CONST -D_CRT_NONSTDC_NO_DEPRECATE -D_CRT_NON_CONFORMING_SWPRINTFS -D_CRT_SECURE_NO_DEPRECATE -D_DEBUG -D_DLL -D_HAS_AUTO_PTR_ETC -D_MT -D_REENTRANT -D_SCL_SECURE_NO_WARNINGS -D_SILENCE_CXX17_CODECVT_HEADER_DEPRECATION_WARNING -D_SILENCE_CXX17_OLD_ALLOCATOR_MEMBERS_DEPRECATION_WARNING -D_SILENCE_CXX17_RESULT_OF_DEPRECATION_WARNING -D_WIN32_WINNT=0x0601 -D_X86_=1 -EHs -GR -GS -Gd -Gs -Gy -MDd -Od -W4 -Wv:18 -Zc:__cplusplus -Zm500 -bigobj -nologo -permissive- -std:c++17 -utf-8 -wd4127 -wd4201 -wd4244 -wd4250 -wd4251 -wd4267 -wd4275 -wd4505 -wd4611 -wd4706
>  reason :    -DZLIB_CONST -DZLIB_CONST
> Incorrect precompiled header setup or internal gbuild error.
> make[1]: *** [C:/cygwin/home/tdf/jenkins/workspace/gerrit_windows/writerperfect/Library_wpftdraw.mk:31: C:/cygwin/home/tdf/jenkins/workspace/gerrit_windows/workdir/PrecompiledHeader/nodebug/Timestamps/Library_wpftdraw_reuse] Error 1

with --enable-pch.)

Change-Id: Iadd3c90a65993ebef98190458762b1c86d425c4d
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/119961
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/sdext/source/pdfimport/xpdfwrapper/pnghelper.cxx b/sdext/source/pdfimport/xpdfwrapper/pnghelper.cxx
index a6390f0157e9..798555fe2f54 100644
--- a/sdext/source/pdfimport/xpdfwrapper/pnghelper.cxx
+++ b/sdext/source/pdfimport/xpdfwrapper/pnghelper.cxx
@@ -86,7 +86,7 @@ sal_uInt32 PngHelper::deflateBuffer( const Output_t* i_pBuf, size_t i_nLen, Outp
     if (Z_OK != deflateInit(&aStream, Z_BEST_COMPRESSION))
         return 0;
     aStream.avail_in = uInt(i_nLen);
-    aStream.next_in = const_cast<Bytef*>(i_pBuf);
+    aStream.next_in = i_pBuf;
 
     sal_uInt8 aOutBuf[ 32768 ];
     do