+20160903
+ + correct 20100515 change for weak signals versus sigprocmask (report
+ by Rich Coe).
+ + modify misc/Makefile.in to work around OpenBSD "make" which unlike
+ all other versions of "make" does not recognize continuation lines
+ of comments.
+ + amend the last change to CF_C_ENV_FLAGS to move only the
+ preprocessor, optimization and warning flags to CPPFLAGS and CFLAGS,
+ leaving the residue in CC. That happens to work for gcc's various
+ "model" options, but may require tuning for other compilers (report
+ by Sven Joachim).
+