MFC r240468 (by brooks):

MFC r240468 (by brooks):

  Introduce a new make variable COMPILER_TYPE that specifies what
  type of compiler is being used (currently clang or gcc).  COMPILER_TYPE
  is set in the new bsd.compiler.mk file based on the value of the CC
  variable or, should it prove informative, by running ${CC} --version
  and examining the output.

  To avoid negative performance impacts in the default case and correct
  value for COMPILER_TYPE type is determined and passed in the environment
  of submake instances while building world.

  Replace adhoc attempts at determining the compiler type by examining
  CC or MK_CLANG_IS_CC with checks of COMPILER_TYPE.  This eliminates
  bootstrapping complications when first setting WITH_CLANG_IS_CC.

  Sponsored by:	DARPA, AFRL
  Reviewed by:	Yamaya Takashi <yamayan@kbh.biglobe.ne.jp>, imp, linimon
		(with some modifications post review)

MFC r242633 (by brooks):

  Allow CC to be gcc46 or similar by matching gcc*.

  Don't test the value of the :M matches, either the string matches or does
  not.

MFC r242658:

  Fix typo in bsd.compiler.mk.

git-svn-id: svn://svn.freebsd.org/base/stable/9@243041 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f