The error is
Building native extensions. This could take a while...
ERROR: Error installing libxml-ruby:
ERROR: Failed to build gem native extension.
current directory: /Users/<username>/.rbenv/versions/2.3.7/lib/ruby/gems/2.3.0/gems/libxml-ruby-3.1.0/ext/libxml
/Users/<username>/.rbenv/versions/2.3.7/bin/ruby -r ./siteconf20190523-40908-1mq6z0c.rb extconf.rb
checking for libxml/xmlversion.h in /opt/include/libxml2,/opt/local/include/libxml2,/usr/local/include/libxml2,/usr/include/libxml2... no
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers. Check the mkmf.log file for more details. You may
need configuration options.
and logs are
find_header: checking for libxml/xmlversion.h in /opt/include/libxml2,/opt/local/include/libxml2,/usr/local/include/libxml2,/usr/include/libxml2... -------------------- no
"clang -o conftest -I/Users/<username>/.rbenv/versions/2.3.7/include/ruby-2.3.0/x86_64-darwin18 -I/Users/<username>/.rbenv/versions/2.3.7/include/ruby-2.3.0/ruby/backward -I/Users/<username>/.rbenv/versions/2.3.7/include/ruby-2.3.0 -I. -I/Users/<username>/.rbenv/versions/2.3.7/include -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT -O3 -Wno-error=shorten-64-to-32 -pipe conftest.c -L. -L/Users/<username>/.rbenv/versions/2.3.7/lib -L. -L/Users/<username>/.rbenv/versions/2.3.7/lib -fstack-protector -L/usr/local/lib -lruby-static -framework Foundation -lpthread -lgmp -ldl -lobjc "
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: int main(int argc, char **argv)
4: {
5: return 0;
6: }
/* end */
"clang -E -I/Users/<username>/.rbenv/versions/2.3.7/include/ruby-2.3.0/x86_64-darwin18 -I/Users/<username>/.rbenv/versions/2.3.7/include/ruby-2.3.0/ruby/backward -I/Users/<username>/.rbenv/versions/2.3.7/include/ruby-2.3.0 -I. -I/Users/<username>/.rbenv/versions/2.3.7/include -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT -O3 -Wno-error=shorten-64-to-32 -pipe conftest.c -o conftest.i"
conftest.c:3:10: fatal error: 'libxml/xmlversion.h' file not found
#include <libxml/xmlversion.h>
^~~~~~~~~~~~~~~~~~~~~
1 error generated.
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: #include <libxml/xmlversion.h>
/* end */
"clang -E -I/Users/<username>/.rbenv/versions/2.3.7/include/ruby-2.3.0/x86_64-darwin18 -I/Users/<username>/.rbenv/versions/2.3.7/include/ruby-2.3.0/ruby/backward -I/Users/<username>/.rbenv/versions/2.3.7/include/ruby-2.3.0 -I. -I/Users/<username>/.rbenv/versions/2.3.7/include -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT -O3 -Wno-error=shorten-64-to-32 -pipe -I/opt/include/libxml2 conftest.c -o conftest.i"
conftest.c:3:10: fatal error: 'libxml/xmlversion.h' file not found
#include <libxml/xmlversion.h>
^~~~~~~~~~~~~~~~~~~~~
1 error generated.
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: #include <libxml/xmlversion.h>
/* end */
"clang -E -I/Users/<username>/.rbenv/versions/2.3.7/include/ruby-2.3.0/x86_64-darwin18 -I/Users/<username>/.rbenv/versions/2.3.7/include/ruby-2.3.0/ruby/backward -I/Users/<username>/.rbenv/versions/2.3.7/include/ruby-2.3.0 -I. -I/Users/<username>/.rbenv/versions/2.3.7/include -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT -O3 -Wno-error=shorten-64-to-32 -pipe -I/opt/local/include/libxml2 conftest.c -o conftest.i"
conftest.c:3:10: fatal error: 'libxml/xmlversion.h' file not found
#include <libxml/xmlversion.h>
^~~~~~~~~~~~~~~~~~~~~
1 error generated.
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: #include <libxml/xmlversion.h>
/* end */
"clang -E -I/Users/<username>/.rbenv/versions/2.3.7/include/ruby-2.3.0/x86_64-darwin18 -I/Users/<username>/.rbenv/versions/2.3.7/include/ruby-2.3.0/ruby/backward -I/Users/<username>/.rbenv/versions/2.3.7/include/ruby-2.3.0 -I. -I/Users/<username>/.rbenv/versions/2.3.7/include -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT -O3 -Wno-error=shorten-64-to-32 -pipe -I/usr/local/include/libxml2 conftest.c -o conftest.i"
conftest.c:3:10: fatal error: 'libxml/xmlversion.h' file not found
#include <libxml/xmlversion.h>
^~~~~~~~~~~~~~~~~~~~~
1 error generated.
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: #include <libxml/xmlversion.h>
/* end */
"clang -E -I/Users/<username>/.rbenv/versions/2.3.7/include/ruby-2.3.0/x86_64-darwin18 -I/Users/<username>/.rbenv/versions/2.3.7/include/ruby-2.3.0/ruby/backward -I/Users/<username>/.rbenv/versions/2.3.7/include/ruby-2.3.0 -I. -I/Users/<username>/.rbenv/versions/2.3.7/include -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT -O3 -Wno-error=shorten-64-to-32 -pipe -I/usr/include/libxml2 conftest.c -o conftest.i"
conftest.c:3:10: fatal error: 'libxml/xmlversion.h' file not found
#include <libxml/xmlversion.h>
^~~~~~~~~~~~~~~~~~~~~
1 error generated.
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: #include <libxml/xmlversion.h>
/* end */
--------------------
a lib can not be found,
Solution:
- Step 1:
brew install libxml2// install the missing lib - Step 2:
gem install libxml-ruby -v '3.0.0' -- --with-xml2-config=/usr/local/opt/libxml2/bin/xml2-config --with-xml2-dir=/usr/local/opt/libxml2 --with-xml2-lib=/usr/local/opt/libxml2/lib --with-xml2-include=/usr/local/opt/libxml2/include// install with special lib path