redhat linux install fails with error "extconf.rb:160:in `<main>': uninitialized constant CONFTEST (NameError)"

[dub357]

[root@dbl2 ~]# gem install ruby-oci8
Building native extensions. This could take a while...
ERROR: Error installing ruby-oci8:
ERROR: Failed to build gem native extension.

/usr/bin/ruby extconf.rb

attempting to locate oracle-instantclient...
checking load library path...
LD_LIBRARY_PATH...
checking /dbo/oracle/product/18.3/lib... yes
/dbo/oracle/product/18.3/lib/libclntsh.so.10.1 looks like a full client.
checking for cc... ok
checking for gcc... yes
checking for LP64... yes
checking for sys/types.h... yes
checking for ruby header... ok
Get the version of Oracle from SQL*Plus... 1800
try -I/dbo/oracle/product/18.3/rdbms/public
checking for oci.h... yes
checking for OCIEnvCreate() in oci.h... yes
checking for OCI_MAJOR_VERSION in oci.h... 18
checking for OCI_MINOR_VERSION in oci.h... 13
checking for localtime_r()... yes
checking for dladdr()... yes
checking for dlmodinfo()... no
checking for dlgetname()... no
checking for ruby/thread.h... yes
checking for rb_class_superclass() in ruby.h... yes
checking for rb_thread_call_without_gvl() in ruby/thread.h... yes
checking for rb_sym2str() in ruby.h... no
checking for plthook... *** 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.

Provided configuration options:
--with-opt-dir
--without-opt-dir
--with-opt-include
--without-opt-include=${opt-dir}/include
--with-opt-lib
--without-opt-lib=${opt-dir}/lib64
--with-make-prog
--without-make-prog
--srcdir=.
--curdir
--ruby=/usr/bin/ruby
--with-instant-client
--without-instant-client
--with-instant-client-dir
--without-instant-client-dir
--with-instant-client-include
--without-instant-client-include=${instant-client-dir}/include
--with-instant-client-lib
--without-instant-client-lib=${instant-client-dir}/
--with-oracle-version
--without-oracle-version
--with-runtime-check
--without-runtime-check
extconf.rb:160:in `

': uninitialized constant CONFTEST (NameError)

Gem files will remain installed in /usr/local/share/gems/gems/ruby-oci8-2.2.9 for inspection.
Results logged to /usr/local/share/gems/gems/ruby-oci8-2.2.9/ext/oci8/gem_make.out
)

Linux version:
[root@dbl2 ~]# lsb_release -a
LSB Version: :core-4.1-amd64:core-4.1-noarch
Distributor ID: RedHatEnterpriseWorkstation
Description: Red Hat Enterprise Linux Workstation release 7.9 (Maipo)
Release: 7.9
Codename: Maipo

[kubo]

Could you use ruby 2.1.0 or later?
Otherwise, could you replace this line with FileUtils.rm_f("conftest.#{$OBJEXT}")?

[dub357]

I'm not sure what Ruby 2.1.0 would do to fix this but I can try a bit later. In the meantime, I tried 2.1.8 based on the README note "Use ruby-oci8 2.1.8 for ruby 1.8" and it installed successfully.

[root@dbl2 ~]# gem install ruby-oci8 --version 2.1.8
Fetching: ruby-oci8-2.1.8.gem (100%)
Building native extensions. This could take a while...
Successfully installed ruby-oci8-2.1.8
Parsing documentation for ruby-oci8-2.1.8
Installing ri documentation for ruby-oci8-2.1.8
1 gem installed