Add Maintenance.clear_sources_cache()

This is a maintenance command that clears out the sources caches that we
use to speed up build environment construction.  It's mostly useful for
debugging.

Author: staticfloat

src/Maintenance.jl

@@ -3,6 +3,7 @@ module Maintenance
 # This file will collect entrypoints for maintenance of a build system.
 using Ccache_jll
 import ..BinaryBuilder2: ccache_cache
+import ..BinaryBuilderSources: generated_source_cache, jll_resolve_cache
 
 function ccache_env(cmd::Cmd)
     return addenv(cmd, "CCACHE_DIR" => ccache_cache())
@@ -33,6 +34,11 @@ function ccache_show_stats()
     run(ccache_env(`$(ccache()) --show-stats --show-compression --verbose`))
 end
 
+function clear_sources_cache()
+    rm(generated_source_cache("."); recursive=true, force=true)
+    rm(jll_resolve_cache("."); recursive=true, force=true)
+end
+
 # TODO:
 #  - artifact LRU trimming?
 #  - Old universe deletion?