kbuild: in headers_install autoconvert asm/inline/volatile to __xxx__

Headers in userspace should be using the __xxx__ form of the asm, inline,
and volatile keywords.  Since people like to revert these things without
realizing what's going on, have the headers install step autoconvert these
keywords.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

scripts/headers_install.pl

@@ -36,6 +36,9 @@
 		$line =~ s/\s__attribute_const__\s/ /g;
 		$line =~ s/\s__attribute_const__$//g;
 		$line =~ s/^#include <linux\/compiler.h>//;
+		$line =~ s/(^|\s)(inline)\b/$1__$2__/g;
+		$line =~ s/(^|\s)(asm)\b(\s|[(]|$)/$1__$2__$3/g;
+		$line =~ s/(^|\s|[(])(volatile)\b(\s|[(]|$)/$1__$2__$3/g;
 		printf OUTFILE "%s", $line;
 	}
 	close OUTFILE;