*FLAGS_FOR_BUILD vs cross-compiling

[Mike Frysinger <vapier at gentoo dot org>]

the toplevel configure.ac currently does:
CFLAGS_FOR_BUILD=${CFLAGS_FOR_BUILD-${CFLAGS}}
CXXFLAGS_FOR_BUILD=${CXXFLAGS_FOR_BUILD-${CFLAGS}}
LDFLAGS_FOR_BUILD=${LDFLAGS_FOR_BUILD-${CFLAGS}}

there's two things wrong here ... first, the default for CXXFLAGS/LDFLAGS 
should be CXXFLAGS/LDFLAGS, not CFLAGS.  the other is that FOR_BUILD 
variables should not default to the host flags if $host != $build.  the 
program FOR_BUILD variables (like AR/RANLIB/etc...) already test this, but 
the *FLAGS do not.  so if you try to build like:
CFLAGS="-m4" ./configure --build=x86_64-... --host=sh4-... --target=sh4-...
it'll fail if any build binaries need to be compiled (like the "chew" binary 
in bfd/doc/).

the attached patch should rectify both of these issues.
-mike

2007-10-06  Mike Frysinger  <vapier@gentoo.org>

	* configure.ac (CFLAGS_FOR_BUILD, CXXFLAGS_FOR_BUILD,
	LDFLAGS_FOR_BUILD): Default them to host flags only for $host = $build.
	Set default CXXFLAGS_FOR_BUILD to CXXFLAGS, not CFLAGS.  Set default
	LDFLAGS_FOR_BUILD to LDFLAGS, not CFLAGS.
	* configure: Regenerate.

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2007-10-06  Mike Frysinger  <vapier@gentoo.org>

	* configure.ac (CFLAGS_FOR_BUILD, CXXFLAGS_FOR_BUILD,
	LDFLAGS_FOR_BUILD): Default them to host flags only for $host = $build.
	Set default CXXFLAGS_FOR_BUILD to CXXFLAGS, not CFLAGS.  Set default
	LDFLAGS_FOR_BUILD to LDFLAGS, not CFLAGS.
	* configure: Regenerate.

--- configure.ac	1 Oct 2007 07:55:47 -0000	1.30
+++ configure.ac	6 Oct 2007 23:06:00 -0000
@@ -2387,9 +2387,11 @@ esac
 
 # Allow the user to override the flags for
 # our build compiler if desired.
-CFLAGS_FOR_BUILD=${CFLAGS_FOR_BUILD-${CFLAGS}}
-CXXFLAGS_FOR_BUILD=${CXXFLAGS_FOR_BUILD-${CFLAGS}}
-LDFLAGS_FOR_BUILD=${LDFLAGS_FOR_BUILD-${CFLAGS}}
+if test x"${build}" = x"${host}" ; then
+  CFLAGS_FOR_BUILD=${CFLAGS_FOR_BUILD-${CFLAGS}}
+  CXXFLAGS_FOR_BUILD=${CXXFLAGS_FOR_BUILD-${CXXFLAGS}}
+  LDFLAGS_FOR_BUILD=${LDFLAGS_FOR_BUILD-${LDFLAGS}}
+fi
 
 # On Canadian crosses, we'll be searching the right directories for
 # the previously-installed cross compiler, so don't bother to add