internal/rosa/package: migrate many libraries

This also adds more string helpers.

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

internal/rosa/package/libexpat.az

@@ -0,0 +1,22 @@
+package libexpat {
+	description = "a stream-oriented XML parser library";
+	website = "https://libexpat.github.io";
+	anitya = 770;
+
+	version* = "2.8.1";
+	source = remoteGitHubRelease {
+		suffix = "libexpat/libexpat";
+		tag = "R_"+replace {
+			s = version;
+			old = ".";
+			new = "_";
+		};
+		name = "expat-"+version+".tar.bz2";
+		checksum = "iMEtbOJhQfGof2GxSlxffQSI1va_NDDQ9VIuqcPbNZ0291Dr8wttD5QecYyjIQap";
+		compress = bzip2;
+	};
+
+	exec = make {};
+
+	inputs = [ bash ];
+}