Comment # 3 on bug 1169441 from Dominique Leuenberger

to make it clear: I only mean the include path fixed itself -not the build;
curretnly ti fails like:

[  397s] libtool: compile:  g++ -DHAVE_CONFIG_H -I. -I../.. -I../..
-I/usr/include/ruby-2.7.0 -I/usr/include/ruby-2.7.0/x86_64-linux-gnu -fPIC
-DPIC -O2 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector-strong -funwind-tables
-fasynchronous-unwind-tables -fstack-clash-protection -Werror=return-type
-flto=auto -g -DNDEBUG -std=c++14 -Wall -Wextra -Wformat -Wnon-virtual-dtor
-Wno-unused-parameter -Wsuggest-override -I/usr/include/libxml2
-I/usr/include/json-c -c storage_wrap.cxx  -fPIC -DPIC -o .libs/storage_wrap.o
[  398s] storage_wrap.cxx: In function 'void SWIG_RubyInitializeTrackings()':
[  398s] storage_wrap.cxx:1268:85: error: call of overloaded
'rb_define_virtual_variable(const char [21], VALUE (&)(...), NULL)' is
ambiguous
[  398s]  1268 |   rb_define_virtual_variable("SWIG_TRACKINGS_COUNT",
swig_ruby_trackings_count, NULL);