internal/rosa/package: migrate many libraries

This also adds more string helpers.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/rosa/package/libffi.az

@@ -0,0 +1,18 @@
+package libffi {
+	description = "a portable, high level programming interface to various calling conventions";
+	website = "https://sourceware.org/libffi";
+	anitya = 1611;
+
+	version* = "3.5.2";
+	source = remoteGitHubRelease {
+		suffix = "libffi/libffi";
+		tag = "v"+version;
+		name = "libffi-"+version+".tar.gz";
+		checksum = "2_Q-ZNBBbVhltfL5zEr0wljxPegUimTK4VeMSiwJEGksls3n4gj3lV0Ly3vviSFH";
+		compress = gzip;
+	};
+
+	exec = make {};
+
+	inputs = [ kernel-headers ];
+}