Add external/musl to the bp2build allowlists

Add external/musl to the bp2build allowlists.  Disable libc_musl_sysroot,
which fails due to a $(locations) reference to a glob that is
unsupported in bazel.

Bug: 259266326
Test: //external/musl:libc_musl builds
Change-Id: Icf0ea2f89854ba3605096dcaa95c1c829af34dc3
diff --git a/android/allowlists/allowlists.go b/android/allowlists/allowlists.go
index e7bd920..957d3ea 100644
--- a/android/allowlists/allowlists.go
+++ b/android/allowlists/allowlists.go
@@ -164,6 +164,7 @@
 		"external/lzma/C":                        Bp2BuildDefaultTrueRecursively,
 		"external/mdnsresponder":                 Bp2BuildDefaultTrueRecursively,
 		"external/minijail":                      Bp2BuildDefaultTrueRecursively,
+		"external/musl":                          Bp2BuildDefaultTrueRecursively,
 		"external/objenesis":                     Bp2BuildDefaultTrueRecursively,
 		"external/openscreen":                    Bp2BuildDefaultTrueRecursively,
 		"external/ow2-asm":                       Bp2BuildDefaultTrueRecursively,
@@ -1305,6 +1306,9 @@
 		// TODO(b/254476335): disable the following due to this bug
 		"libapexinfo",
 		"libapexinfo_tests",
+
+		// uses glob in $(locations)
+		"libc_musl_sysroot",
 	}
 
 	Bp2buildCcLibraryStaticOnlyList = []string{}