bison: Fix hard-coded m4 path

sys-devel/bison/bison-2.4.3.recipe

@@ -16,7 +16,7 @@ COPYRIGHT="1992-2010 Free Software Foundation, Inc."
 LICENSE="GNU GPL v3"
 SRC_URI="http://ftp.gnu.org/gnu/bison/bison-2.4.3.tar.gz"
 CHECKSUM_MD5="ea45c778b36bdc7a720096819e292a73"
-REVISION="5"
+REVISION="6"
 ARCHITECTURES="x86_gcc2 x86 x86_64"
 
 PATCHES="bison-2.4.3.patch"
@@ -29,6 +29,7 @@ PROVIDES="
 	"
 REQUIRES="
 	haiku >= $haikuVersion
+	cmd:m4
 	"
 BUILD_REQUIRES="
 	"
@@ -47,7 +48,7 @@ BUILD()
 {
 	# bison looks for m4 in an absolute path, but uses that only within
 	# its own testsuite, so we let it be ...
-	runConfigure ./configure \
+	M4=$portPackageLinksDir/cmd~m4/bin/m4 runConfigure ./configure \
 		--disable-rpath --with-gnu-ld
 	make $jobArgs
 }