Mixed builds: propagate includes from cc_* targets

This allows us to remove libasync_safe from the mixed builds denylist.

Test: mixed_libc.sh CI script
Change-Id: Ibafd231284864078bf30340f919d39e5098843ce
diff --git a/cc/library.go b/cc/library.go
index 3ac7e11..73215ed 100644
--- a/cc/library.go
+++ b/cc/library.go
@@ -402,11 +402,18 @@
 
 func (f *flagExporter) setProvider(ctx android.ModuleContext) {
 	ctx.SetProvider(FlagExporterInfoProvider, FlagExporterInfo{
-		IncludeDirs:       android.FirstUniquePaths(f.dirs),
+		// Comes from Export_include_dirs property, and those of exported transitive deps
+		IncludeDirs: android.FirstUniquePaths(f.dirs),
+		// Comes from Export_system_include_dirs property, and those of exported transitive deps
 		SystemIncludeDirs: android.FirstUniquePaths(f.systemDirs),
-		Flags:             f.flags,
-		Deps:              f.deps,
-		GeneratedHeaders:  f.headers,
+		// Used in very few places as a one-off way of adding extra defines.
+		Flags: f.flags,
+		// Used sparingly, for extra files that need to be explicitly exported to dependers,
+		// or for phony files to minimize ninja.
+		Deps: f.deps,
+		// For exported generated headers, such as exported aidl headers, proto headers, or
+		// sysprop headers.
+		GeneratedHeaders: f.headers,
 	})
 }
 
@@ -524,6 +531,8 @@
 			Direct(outputFilePath).
 			Build(),
 	})
+
+	ctx.SetProvider(FlagExporterInfoProvider, flagExporterInfoFromCcInfo(ctx, ccInfo))
 	if i, ok := handler.module.linker.(snapshotLibraryInterface); ok {
 		// Dependencies on this library will expect collectedSnapshotHeaders to
 		// be set, otherwise validation will fail. For now, set this to an empty