Add a separate Makefile for the version string plus GOARCH. To be used
by Go packages.
Changes 4.6.6:
* NEW linetype keyword "nodraw" can be used to draw only the points in "with lp"
* NEW plot option to "skip N" lines at start of an ascii data file
* NEW 'set fit prescale' normalized fit parameters before M-L refinement
* NEW update svg terminal to grey out the key entry when a plot is toggled off
* NEW allow keywords "comma" and "tab" for "set datafile separator"
* CHANGE Accept "with image pixels" as a synonym for "with image failsafe"
* CHANGE return NaN if a requested numerical data value finds a string instead
* CHANGE Consume only one space following the font name in an enhanced test string
* CHANGE respond to left mouse click on press rather than on release
* FIX Faster recovery from outboard server gnuplot_qt being killed
* FIX get rid of O(N^2) memory allocation for string data in long input lines
* FIX large integers in iteration spec could cause overflow in end condition check
* FIX object fillcolors should be consistent with the color of current linetypes
* FIX LFS support on 64bit platforms (not backported for 32bit platforms)
* FIX timecolumn() applied to non-axis data reports an error rather than faulting
* FIX clipping could fail on integer overflow
* FIX segfault resulting from strcol(N) applied to empty field in a *.csv file
* FIX adjustment of key size to accommodate long key title
* FIX treat data value read as "NaN" the same as we would "1/0"
* FIX handling of events triggered by closing the qt plot window
* FIX iteration failure due to integer overflow
* FIX clip r axis tics to current plot boundary
* FIX logscale cb axis with volatile data
* FIX qt terminal timing problem with mouse click+release
* FIX qt terminal handle window close events
* FIX incorrect processing of certain loop [start:end:incr] combinations
* FIX Fix y extent and clipping of rectangles with y coord < 0 or inverted axes
* FIX handle columnheaders in input to fit
* FIX add sanity check in pdf.trm to avoid strcpy(fontname,fontname)
Updated graphics/gnuplot to 4.6.6
Sync MACHINE_ARCH -> GNU_ARCH mapping table with NetBSD. Most noticable
change outside ARM is going to i486 as platform name for x86.