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.

dev-embedded/stlink/stlink-1.6.1.recipe

@@ -10,7 +10,7 @@ SOURCE_URI="https://github.com/texane/stlink/archive/v$portVersion.tar.gz"
 CHECKSUM_SHA256="ca9a640f84c3e2c9873bd51759594bc05c00cdf6e1f21b434ae2c0e7985433d8"
 PATCHES="stlink-$portVersion.patchset"
 
-ARCHITECTURES="!x86_gcc2 x86_64"
+ARCHITECTURES="all !x86_gcc2"
 SECONDARY_ARCHITECTURES="x86"
 
 commandSuffix=$secondaryArchSuffix
@@ -48,7 +48,7 @@ BUILD()
 {
 	mkdir -p build
 	cd build
-	
+
 	cmake .. -DCMAKE_BUILD_TYPE=Release
 	make $jobArgs
 }