patch-src_Makefile.in

  invoked FdTOx (convert floating point to 64-bit integer) instruction
  with odd register number as the second argument, while apparently[*]
  an even number is required:

	fdtox	%f10, %f15

  It caused ``Illegal operands'' error when compiling `draw_symbols.c':

	{standard input}: Assembler messages:
	{standard input}:2686: Error: Illegal operands
	{standard input}:2695: Error: Illegal operands
	{standard input}:2835: Error: Illegal operands
	{standard input}:2844: Error: Illegal operands
	{standard input}:2854: Error: Illegal operands
	{standard input}:2864: Error: Illegal operands

  Fix the build by forcing -O0 when compiling this file on sparc64.

- Remove OPTCFLAGS option which enabled "optimized" CFLAGS ``-O2 -pipe'':
  these are our default CFLAGS for a long time

[*] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56890