The connector was advertised in the past as a libmysqlclient drop-in replacement.
However you seem to be renaming include files in 3.x which breaks source code compatibility with the majority of programs that was written for that.
It this intended?

Dovecot:

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driver-mysql.c:24:20: fatal error: errmsg.h: No such file or directory
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PHP:

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php-7.0.9/ext/mysqli/php_mysqli_structs.h:63:23: fatal error: my_global.h: No such file or directory
compilation terminated.
==

(yes, I know I could use mysqlnd instead, but that's not the point)

Kodi:

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mysqldataset.cpp:34:26: fatal error: mysql/errmsg.h: No such file or directory
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Along with other include file related errors.
E.g. Qt 4, Qt 5 and poco library are missing the definition for my_ulonglong:

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drivers/mysql/qsql_mysql.cpp:562:5: error: ‘my_ulonglong’ was not declared in this scope
my_ulonglong numRows;

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../../../sql/drivers/mysql/qsql_mysql.cpp:553:5: error: ‘my_ulonglong’ was not declared in this scope
my_ulonglong numRows;
==
src/StatementExecutor.cpp: In member function ‘void Poco::Data::MySQL::StatementExecutor::execute()’:
src/StatementExecutor.cpp:110:2: error: ‘my_ulonglong’ was not declared in this scope
my_ulonglong affectedRows = mysql_affected_rows(_pSessionHandle);
==