[PATCH] build compile.h earlier

compile.h is created super-late in the build.  But proc_misc.c want to include
it, and it's generally not sane to have a header file in include/linux be
created at the end of the build: it's either not present or, worse, wrong for
most of the build.

So the patch arranges for compile.h to be built at the start of the build
process.  It also consolidates the compile.h rules with those for version.h
and utsname.h, so they all get built together.

I hope.  My chances of having got this right are about 2%.

Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Makefile

@@ -368,10 +368,14 @@ endif
 # Detect when mixed targets is specified, and make a second invocation
 # of make so .config is not included in this case either (for *config).
 
-no-dot-config-targets := clean mrproper distclean \
+PHONY += generated_headers
+
+generated_headers: include/linux/version.h include/linux/compile.h \
+		include/linux/utsrelease.h
+
+no-dot-config-targets := generated_headers clean mrproper distclean \
 			 cscope TAGS tags help %docs check% \
-			 include/linux/version.h headers_% \
-			 kernelrelease kernelversion
+			 headers_% kernelrelease kernelversion
 
 config-targets := 0
 mixed-targets  := 0
@@ -734,6 +738,16 @@ debug_kallsyms: .tmp_map$(last_kallsyms)
 
 endif # ifdef CONFIG_KALLSYMS
 
+# compile.h changes depending on hostname, generation number, etc,
+# so we regenerate it always.
+# mkcompile_h will make sure to only update the
+# actual file if its content has changed.
+
+include/linux/compile.h: FORCE
+	@echo '  CHK     $@'
+	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/mkcompile_h $@ \
+	"$(UTS_MACHINE)" "$(CONFIG_SMP)" "$(CONFIG_PREEMPT)" "$(CC) $(CFLAGS)"
+
 # vmlinux image - including updated kernel symbols
 vmlinux: $(vmlinux-lds) $(vmlinux-init) $(vmlinux-main) $(kallsyms.o) FORCE
 ifdef CONFIG_HEADERS_CHECK
@@ -852,8 +866,8 @@ endif
 # prepare2 creates a makefile if using a separate output directory
 prepare2: prepare3 outputmakefile
 
-prepare1: prepare2 include/linux/version.h include/linux/utsrelease.h \
-                   include/asm include/config/auto.conf
+prepare1: prepare2 generated_headers include/asm include/config/auto.conf
+
 ifneq ($(KBUILD_MODULES),)
 	$(Q)mkdir -p $(MODVERDIR)
 	$(Q)rm -f $(MODVERDIR)/*
@@ -922,14 +936,14 @@ export INSTALL_HDR_PATH
 HDRARCHES=$(filter-out generic,$(patsubst $(srctree)/include/asm-%/Kbuild,%,$(wildcard $(srctree)/include/asm-*/Kbuild)))
 
 PHONY += headers_install_all
-headers_install_all: include/linux/version.h scripts_basic FORCE
+headers_install_all: generated_headers scripts_basic FORCE
 	$(Q)$(MAKE) $(build)=scripts scripts/unifdef
 	$(Q)for arch in $(HDRARCHES); do \
 	 $(MAKE) ARCH=$$arch -f $(srctree)/scripts/Makefile.headersinst obj=include BIASMDIR=-bi-$$arch ;\
 	 done
 
 PHONY += headers_install
-headers_install: include/linux/version.h scripts_basic FORCE
+headers_install: generated_headers scripts_basic FORCE
 	@if [ ! -r $(srctree)/include/asm-$(ARCH)/Kbuild ]; then \
 	  echo '*** Error: Headers not exportable for this architecture ($(ARCH))'; \
 	  exit 1 ; fi
@@ -1026,8 +1040,7 @@ CLEAN_FILES +=	vmlinux System.map \
 # Directories & files removed with 'make mrproper'
 MRPROPER_DIRS  += include/config include2 usr/include
 MRPROPER_FILES += .config .config.old include/asm .version .old_version \
-                  include/linux/autoconf.h include/linux/version.h      \
-                  include/linux/utsrelease.h                            \
+                  include/linux/autoconf.h generated-headers		\
 		  Module.symvers tags TAGS cscope*
 
 # clean - Delete most, but leave enough to build external modules

init/Makefile

@@ -18,12 +18,3 @@ clean-files := ../include/linux/compile.h
 $(obj)/main.o: include/linux/compile.h
 $(obj)/version.o: include/linux/compile.h
 
-# compile.h changes depending on hostname, generation number, etc,
-# so we regenerate it always.
-# mkcompile_h will make sure to only update the
-# actual file if its content has changed.
-
-include/linux/compile.h: FORCE
-	@echo '  CHK     $@'
-	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/mkcompile_h $@ \
-	"$(UTS_MACHINE)" "$(CONFIG_SMP)" "$(CONFIG_PREEMPT)" "$(CC) $(CFLAGS)"