Merge tag 'kbuild-v4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - Clean up Makefiles and scripts

 - Improve clang support

 - Remove unneeded genhdr-y syntax

 - Remove unneeded cc-option-align macro

 - Introduce __cc-option macro and use it to fix x86 boot code compiler
   flags

* tag 'kbuild-v4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kbuild: improve comments on KBUILD_SRC
  x86/build: Specify stack alignment for clang
  x86/build: Use __cc-option for boot code compiler options
  kbuild: Add __cc-option macro
  kbuild: remove cc-option-align
  kbuild: replace genhdr-y with generated-y
  kbuild: clang: Disable 'address-of-packed-member' warning
  kbuild: remove duplicated arch/*/include/generated/uapi include path
  kbuild: speed up checksyscalls.sh
  kbuild: simplify silent build (-s) detection

Documentation/kbuild/makefiles.txt

@@ -45,10 +45,9 @@ This document describes the Linux kernel Makefiles.
 
 	=== 7 Kbuild syntax for exported headers
 		--- 7.1 no-export-headers
-		--- 7.2 genhdr-y
-		--- 7.3 generic-y
-		--- 7.4 generated-y
-		--- 7.5 mandatory-y
+		--- 7.2 generic-y
+		--- 7.3 generated-y
+		--- 7.4 mandatory-y
 
 	=== 8 Kbuild Variables
 	=== 9 Makefile language
@@ -487,22 +486,6 @@ more details, with real examples.
 	respectively.
 	Note: cc-option-yn uses KBUILD_CFLAGS for $(CC) options
 
-    cc-option-align
-	gcc versions >= 3.0 changed the type of options used to specify
-	alignment of functions, loops etc. $(cc-option-align), when used
-	as prefix to the align options, will select the right prefix:
-	gcc < 3.00
-		cc-option-align = -malign
-	gcc >= 3.00
-		cc-option-align = -falign
-
-	Example:
-		KBUILD_CFLAGS += $(cc-option-align)-functions=4
-
-	In the above example, the option -falign-functions=4 is used for
-	gcc >= 3.00. For gcc < 3.00, -malign-functions=4 is used.
-	Note: cc-option-align uses KBUILD_CFLAGS for $(CC) options
-
     cc-disable-warning
 	cc-disable-warning checks if gcc supports a given warning and returns
 	the commandline switch to disable it. This special function is needed,
@@ -1277,18 +1260,7 @@ See subsequent chapter for the syntax of the Kbuild file.
 	avoid exporting specific headers (e.g. kvm.h) on architectures that do
 	not support it. It should be avoided as much as possible.
 
-	--- 7.2 genhdr-y
-
-	genhdr-y specifies asm files to be generated.
-
-		Example:
-			#arch/x86/include/uapi/asm/Kbuild
-			genhdr-y += unistd_32.h
-			genhdr-y += unistd_64.h
-			genhdr-y += unistd_x32.h
-
-
-	--- 7.3 generic-y
+	--- 7.2 generic-y
 
 	If an architecture uses a verbatim copy of a header from
 	include/asm-generic then this is listed in the file
@@ -1315,11 +1287,10 @@ See subsequent chapter for the syntax of the Kbuild file.
 		Example: termios.h
 			#include <asm-generic/termios.h>
 
-	--- 7.4 generated-y
+	--- 7.3 generated-y
 
 	If an architecture generates other header files alongside generic-y
-	wrappers, and not included in genhdr-y, then generated-y specifies
-	them.
+	wrappers, generated-y specifies them.
 
 	This prevents them being treated as stale asm-generic wrappers and
 	removed.