how can i compile against zlib system library

[martinkg]

Hi,

i want to compile helm for Fedora 29, but i want to compile it against the zlib system library. I changed the following in the source code:

# use system library zlib
rm -rf ./JUCE/modules/juce_core/zip/zlib/zlib.h
sed -i 's|#define JUCE_INCLUDE_ZLIB_CODE 1|#define JUCE_INCLUDE_ZLIB_CODE 0|' JUCE/modules/juce_core/juce_core.h
sed -i 's|#include "../../../juce_core/zip/zlib/zlib.h"|#include "zlib.h"|' JUCE/modules/juce_graphics/image_formats/pnglib/pngstruct.h

but the compilation fails with this errors:

../../../JUCE/modules/juce_graphics/native/juce_RenderingHelpers.h:1915:14:   required from here
../../../JUCE/modules/juce_graphics/native/juce_RenderingHelpers.h:969:24: warning: 'void* memcpy(void*, const void*, size_t)' writing to an object of non-trivially copyable type 'class juce::PixelAlpha'; use copy-assignment or copy-initialization instead [-Wclass-memaccess]
                 memcpy (dest, src, (size_t) (width * srcStride));
                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from ../../../JUCE/modules/juce_graphics/juce_graphics.h:112,
                 from ../../../JUCE/modules/juce_gui_basics/juce_gui_basics.h:57,
                 from ../../../JUCE/modules/juce_gui_basics/juce_gui_basics.cpp:45,
                 from ../../JuceLibraryCode/include_juce_gui_basics.cpp:9:
../../../JUCE/modules/juce_graphics/colour/juce_PixelFormats.h:617:17: note: 'class juce::PixelAlpha' declared here
 class JUCE_API  PixelAlpha
                 ^~~~~~~~~~
make[1]: Leaving directory '/home/martin/rpmbuild/BUILD/helm-abdedd527e6e1cf86636f0f1e8a3e75b06ed166a/standalone/builds/linux'
make: *** [Makefile:79: standalone] Error 2

Regards Martin