While attempting to build an Oracle RM Switch Module for XA on Unix/Linux platforms as documented here, you may receive one or more errors that the build is unable to find certain Oracle shared objects, and is "skipping incompatible" items.

For example: 

$ ./build ora -r
building 32-bit switch module...
 * Cobsql Integrated Preprocessor
* CSQL-I-018: Invoking Oracle Precompiler/Translator
* CSQL-I-020: Processing output of Oracle Precompiler
* CSQL-I-001: Cobsql has finished returning to the Checker
/usr/bin/ld: skipping incompatible /u01/app/oracle/product/19.0.0/dbhome_1/lib//libclntsh.so when searching for -lclntsh

Full article: https://portal.microfocus.com/s/article/KM000016703