Fix some makeman issues.

- Don't bother looking up REVISION/BRANCH/etc from release/, or the
  CPUTYPE check, as these are not used for makeman and wastes time.  The also
  invokes auto.obj.mk after I reverted auto.obj.mk ignoring -V in r291312.
- Don't modify CC or PATH when WITH_CCACHE_BUILD or WITH_META_MODE is enabled
  as it leads to bsd.compiler.mk errors.

Sponsored by:	EMC / Isilon Storage Division

Makefile.inc1

@@ -163,7 +163,7 @@ OSRELDATE=	0
 .endif
 
 # Set VERSION for CTFMERGE to use via the default CTFFLAGS=-L VERSION.
-.if !defined(VERSION)
+.if !defined(VERSION) && !make(showconfig)
 REVISION!=	${MAKE} -C ${SRCDIR}/release -V REVISION
 BRANCH!=	${MAKE} -C ${SRCDIR}/release -V BRANCH
 SRCRELDATE!=	awk '/^\#define[[:space:]]*__FreeBSD_version/ { print $$3 }' \
@@ -195,11 +195,14 @@ _TARGET_CPUTYPE=${TARGET_CPUTYPE}
 .else
 _TARGET_CPUTYPE=dummy
 .endif
+# Skip for showconfig as it is just wasted time and may invoke auto.obj.mk.
+.if !make(showconfig)
 _CPUTYPE!=	MAKEFLAGS= CPUTYPE=${_TARGET_CPUTYPE} ${MAKE} \
 		-f /dev/null -m ${.CURDIR}/share/mk -V CPUTYPE
 .if ${_CPUTYPE} != ${_TARGET_CPUTYPE}
 .error CPUTYPE global should be set with ?=.
 .endif
+.endif
 .if make(buildworld)
 BUILD_ARCH!=	uname -p
 .if ${MACHINE_ARCH} != ${BUILD_ARCH}

share/mk/bsd.compiler.mk

@@ -30,6 +30,7 @@ __<bsd.compiler.mk>__:
 # Handle ccache after CC is determined, but not if CC/CXX are already
 # overridden with a manual setup.
 .if ${MK_CCACHE_BUILD:Uno} == "yes" && \
+    !make(showconfig) && \
     (${CC:M*ccache/world/*} == "" || ${CXX:M*ccache/world/*} == "")
 # CC is always prepended with the ccache wrapper rather than modifying
 # PATH since it is more clear that ccache is used and avoids wasting time

share/mk/local.meta.sys.mk

@@ -215,6 +215,7 @@ TOOLSDIR?= ${STAGE_HOST_OBJTOP}
 .endif
 # Don't use the bootstrap tools logic on itself.
 .if ${.TARGETS:Mbootstrap-tools} == "" && \
+    !make(showconfig) && \
     !defined(BOOTSTRAPPING_TOOLS) && !empty(TOOLSDIR) && ${.MAKE.LEVEL} == 0
 .for dir in /sbin /bin /usr/sbin /usr/bin
 PATH:= ${TOOLSDIR}${dir}:${PATH}