help me anyone plz

c++ -DHAVE_CONFIG_H -I. -I. -I.. -DSHAPE -DNDEBUG -DNLS -DTIMEDCACHE -DLOCALEPATH=\"/usr/local/share/blackbox/nls\" -DDEFAULTMENU=\"/usr/local/share/blackbox/menu\" -DDEFAULTSTYLE=\"/usr/local/share/blackbox/styles/Results\" -g -O2 -I/usr/X11R6/include -Wall -W -pedantic -c Window.cc
Window.cc: In member function `bool BlackboxWindow::setInputFocus()':
Window.cc:1396: error: `assert' undeclared (first use this function)
Window.cc:1396: error: (Each undeclared identifier is reported only once for
each function it appears in.)
Window.cc: In member function `void
BlackboxWindow::constrain(BlackboxWindow::Corner, unsigned int*, unsigned
int*)':
Window.cc:3234: error: `assert' undeclared (first use this function)
make[2]: *** [Window.o] Error 1
make[2]: Leaving directory `/home/soltek/Mano/Downloads/BlackBox/blackbox-0.65.0/src'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/home/soltek/Mano/Downloads/BlackBox/blackbox-0.65.0'
make: *** [all-recursive-am] Error 2