buildgcc: Define $CMAKE only if clang package is built

This moves the CMAKE definition down into the case statement
for $PACKAGE so that it is only required when the user wants to
build clang.

With this approach, "./buildgcc -P clang" will error out with the
"ERROR: Missing tool:" message if cmake is not installed.

Change-Id: I1e5c1bd67ade8f93ba0390df7f234deb47b9b18a
Signed-off-by: David Hendricks <dhendrix@chromium.org>
Reviewed-on: http://review.coreboot.org/10556
Tested-by: build bot (Jenkins)
Reviewed-by: Francis Rowe <info@gluglug.org.uk>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
diff --git a/util/crossgcc/buildgcc b/util/crossgcc/buildgcc
index 7f440f7..552a6a2 100755
--- a/util/crossgcc/buildgcc
+++ b/util/crossgcc/buildgcc
@@ -165,7 +165,6 @@
 TAR=$(searchtool tar) || exit $?
 PATCH=$(searchtool patch) || exit $?
 MAKE=$(searchtool make) || exit $?
-CMAKE=$(searchtool cmake "cmake") || exit $?
 SHA1SUM=$(searchtool sha1sum)
 SHA512SUM=$(searchtool sha512sum)
 CHECKSUM=$SHA1SUM
@@ -554,6 +553,7 @@
 	CLANG|clang)
 		NAME=clang
 		PACKAGES="LLVM CFE CRT CTE"
+		CMAKE=$(searchtool cmake "cmake") || exit $?
 		;;
 	IASL|iasl)
 		NAME="IASL ACPI compiler"