lsp: prevent some false complaints from LSP clang seeing gcc headers

include/xo/indentlog/machdep/machdep.hpp

@@ -0,0 +1,26 @@
+/* @file machdep.hpp */
+
+#pragma once
+
+/** Carveout for LSP (language server process):
+    LSP uses clang, but with the same compiler flags as primary build.
+    This triggers a handful of false alarms,  in which clang complains about
+    gcc builtins.
+
+    Replace these with something innocuous.  Ok since LSP stops
+    once parsing completes and does not generate code
+ **/
+#if __clang__ && __GNUG__
+
+extern "C" {
+    /* never defined!  must not ever generate code that relies on these */
+    unsigned int fake_mm_getcsr();
+    unsigned int fake_mm_setcsr(unsigned int a);
+}
+
+#define _mm_getcsr(a) fake_mm_getcsr()
+#define _mm_setcsr(a) fake_mm_setcsr(a)
+
+#endif
+
+/* end machdep.hpp */