Upstream: maybe
Description: we should always check for full path
 (i.e.  ZXing/MultiFormatWriter), however those file hierarchy is made
 by installation step, thus libreoffice must use the non-prefix.
 Perhap we should changes the file hierarchy of zxing-cpp project instead?
--- a/configure.ac
+++ b/configure.ac
@@ -11777,35 +11777,16 @@ else
         SYSTEM_ZXING=TRUE
         ZXING_CFLAGS=
         AC_LANG_PUSH([C++])
-        save_CXXFLAGS=$CXXFLAGS
-        save_IFS=$IFS
-        IFS=$P_SEP
-        for i in $CPLUS_INCLUDE_PATH /usr/include; do
-            dnl Reset IFS as soon as possible, to avoid unexpected side effects (and the
-            dnl "/usr/include" fallback makes sure we get here at least once; resetting rather than
-            dnl unsetting follows the advice at <https://git.savannah.gnu.org/gitweb/?p=autoconf.git;
-            dnl a=commitdiff;h=e51c9919f2cf70185b7916ac040bc0bbfd0f743b> "Add recommendation on (not)
-            dnl unsetting IFS."):
-            IFS=$save_IFS
-            dnl TODO: GCC and Clang treat empty paths in CPLUS_INCLUDE_PATH like ".", but we simply
-            dnl ignore them here:
-            if test -z "$i"; then
-                continue
-            fi
-            dnl TODO: White space in $i would cause problems:
-            CXXFLAGS="$save_CXXFLAGS ${CXXFLAGS_CXX11} -I$i/ZXing"
-            AC_CHECK_HEADER(MultiFormatWriter.h, [ZXING_CFLAGS=-I$i/ZXing; break],
-                [unset ac_cv_header_MultiFormatWriter_h], [#include <stdexcept>])
-        done
-        CXXFLAGS=$save_CXXFLAGS
-        if test -z "$ZXING_CFLAGS"; then
+        AC_CHECK_HEADER([ZXing/MultiFormatWriter.h],[],[
             AC_MSG_ERROR(zxing headers not found.)
-        fi
+        ], [
+            AC_INCLUDES_DEFAULT
+            #include <stdexcept>
+        ])
         AC_CHECK_LIB([ZXing], [main], [ZXING_LIBS=-lZXing],
             [ AC_CHECK_LIB([ZXingCore], [main], [ZXING_LIBS=-lZXingCore],
             [ AC_MSG_ERROR(zxing C++ library not found.) ])], [])
         AC_LANG_POP([C++])
-        ZXING_CFLAGS=$(printf '%s' "$ZXING_CFLAGS" | sed -e "s/-I/${ISYSTEM?}/g")
         FilterLibs "${ZXING_LIBS}"
         ZXING_LIBS="${filteredlibs}"
     else
@@ -11822,8 +11803,8 @@ else
     save_CXXFLAGS=$CXXFLAGS
     CXXFLAGS="$CXXFLAGS $CXXFLAGS_CXX11 $ZXING_CFLAGS"
     AC_COMPILE_IFELSE([AC_LANG_SOURCE([
-            #include <BitMatrix.h>
-            #include <BitMatrixIO.h>
+            #include <ZXing/BitMatrix.h>
+            #include <ZXing/BitMatrixIO.h>
             int main(){
                 ZXing::BitMatrix matrix(1, 1);
                 matrix.set(0, 0, true);
--- a/cui/source/dialogs/QrCodeGenDialog.cxx
+++ b/cui/source/dialogs/QrCodeGenDialog.cxx
@@ -19,7 +19,7 @@
 #include <vcl/svapp.hxx>
 
 #if ENABLE_ZXING
-#include <ZXVersion.h>
+#include <ZXing/ZXVersion.h>
 #include <rtl/strbuf.hxx>
 
 #ifdef __GNUC__
@@ -27,20 +27,20 @@
 #pragma GCC diagnostic ignored "-Wshadow"
 #endif
 
-#include <BarcodeFormat.h>
-#include <BitMatrix.h>
-#include <MultiFormatWriter.h>
+#include <ZXing/BarcodeFormat.h>
+#include <ZXing/BitMatrix.h>
+#include <ZXing/MultiFormatWriter.h>
 
 #ifdef __GNUC__
 #pragma GCC diagnostic pop
 #endif
 
 #if HAVE_ZXING_TOSVG
-#include <BitMatrixIO.h>
+#include <ZXing/BitMatrixIO.h>
 #endif
 
 #if ZXING_VERSION_MAJOR < 2
-#include <TextUtfEncoding.h>
+#include <ZXing/TextUtfEncoding.h>
 #endif
 
 #endif // ENABLE_ZXING