updated for version 7.3.1150
Problem:    New regexpengine: Slow when a look-behind match does not have a
	    width specified.
Solution:   Try to compute the maximum width.
Added tag v7-3-1150 for changeset 3dbd251777de
updated for version 7.3.1151
Problem:    New regexp engine: Slow when a look-behind match is followed by a
	    zero-width match.
Solution:   Postpone the look-behind match more often.
Added tag v7-3-1151 for changeset 4d7e3df04256
updated for version 7.3.1152
Problem:    In tiny build ireg_icombine is undefined. (Tony Mechelynck)
Solution:   Add #ifdef.
Added tag v7-3-1152 for changeset 9909e44879b9