Utilize the new "all" ARCHITECTURES keyword in most recipes. (#6189)

x86_64 is used as a baseline: the "x86_64" entry, whatever status it has,
is transformed into "all", and then the other entries in ARCHITECTURES
either dropped or rearranged appropriately.

media-libs/lensfun/lensfun-0.3.2.recipe

@@ -17,7 +17,7 @@ REVISION="3"
 SOURCE_URI="http://sourceforge.net/projects/lensfun/files/$portVersion/lensfun-$portVersion.tar.gz"
 CHECKSUM_SHA256="ae8bcad46614ca47f5bda65b00af4a257a9564a61725df9c74cb260da544d331"
 
-ARCHITECTURES="!x86_gcc2 x86 x86_64"
+ARCHITECTURES="all !x86_gcc2"
 SECONDARY_ARCHITECTURES="!x86_gcc2 x86"
 
 PROVIDES="
@@ -77,7 +77,7 @@ INSTALL()
 {
 	cd cmake_build
 	make install
-	
+
 	mkdir -p $includeDir
 	mv $prefix/include/* $includeDir
 	rmdir $prefix/include
@@ -89,7 +89,7 @@ INSTALL()
 		mv $prefix/lib2/* $libDir
 		rmdir $prefix/bin2 $prefix/lib2
 	fi
-	
+
 	rm -f $binDir/example
 
 	prepareInstalledDevelLibs liblensfun