%APPDATA%/Codeblocks/default.conf contains global environment,
Settings->Environment->Environment Variables. This works fine, there is not incorrect slash modification.
The problem is in
Project->Build options->Custom Variable.
It's from project .cbp file(I've deleted extra info about targets Release and Debug):
<Build>
<Environment>
<Variable name="REMOTE_DIR" value="/mnt/gdb/bin" />
</Environment>
</Build>
Exactly this variable,
REMOTE_DIR from
Project->Build options->Custom Variable has incorrect behavior.
//---------------------------------------------------------------------------------------------------------
And now from
%APPDATA%/Codeblocks/default.conf (but, again, there is not problem):
<envvars>
<sets>
<default>
<ENVVAR0>
<str>
<![CDATA[1|REMOTE_IP|192.168.1.10]]>
</str>
</ENVVAR0>
<ENVVAR1>
<str>
<![CDATA[1|REMOTE_USER|root]]>
</str>
</ENVVAR1>
<ENVVAR2>
<str>
<![CDATA[1|REMOTE_PASSWORD|root]]>
</str>
</ENVVAR2>
<ENVVAR3>
<str>
<![CDATA[1|REMOTE_DIR|/mnt/app/bin]]>
</str>
</ENVVAR3>
</default>
</sets>
<ACTIVE_SET>
<str>
<![CDATA[default]]>
</str>
</ACTIVE_SET>
<DEBUG_LOG bool="0" />
</envvars>