Implement more 'pthread' functions.

Issue #345.
base: increase maximum file name length

This patch increases the maximum file name length to support
'qt5_qnitpickerviewwidget.lib.so'.

Issue #345.
ldso: increase size of managed ELF dataspace

The size needs to be increased for Qt5 libraries.

Issue #345.
qt4: require 'qt4_deprecated' SPECS variable

To avoid build conflicts with Qt5, with this patch, 'qt4_deprecated' needs
to be added to the 'SPECS' variable (in specs.conf) when building for Qt4.

Issue #345.
libports: add Qt5

Fixes #345.