kbuild: Updated make help

Patches originally by Adrian Bunk and Rudmer van Dijk.
Included "make V=0|1" and "make C=1"

Makefile

@@ -789,7 +789,8 @@ help:
 	@echo  'Configuration targets:'
 	@echo  '  oldconfig	  - Update current config utilising a line-oriented program'
 	@echo  '  menuconfig	  - Update current config utilising a menu based program'
-	@echo  '  xconfig	- Update current config utilising a X-based program'
+	@echo  '  xconfig	  - Update current config utilising a QT based front-end'
+	@echo  '  gconfig	  - Update current config utilising a GTK based front-end'
 	@echo  '  defconfig	  - New config with default answer to all options'
 	@echo  '  allmodconfig	  - New config selecting modules when possible'
 	@echo  '  allyesconfig	  - New config where all options are accepted with yes'
@@ -799,7 +800,8 @@ help:
 	@echo  '  all		  - Build all targets marked with [*]'
 	@echo  '* vmlinux	  - Build the bare kernel'
 	@echo  '* modules	  - Build all modules'
-	@echo  '  dir/file.[ois]- Build specified target only'
+	@echo  '  modules_install - Install all modules'
+	@echo  '  dir/file.[ois]  - Build specified target only'
 	@echo  '  rpm		  - Build a kernel as an RPM package'
 	@echo  '  tags/TAGS	  - Generate tags file for editors'
 	@echo  ''
@@ -810,6 +812,9 @@ help:
 	@$(if $(archhelp),$(archhelp),\
 		echo '  No architecture specific help defined for $(ARCH)')
 	@echo  ''
+	@echo  '  make V=0|1 [targets] 0 => quiet build (default), 1 => verbose build'
+	@echo  '  make C=1   [targets] Check all c source with checker tool'
+	@echo  ''
 	@echo  'Execute "make" or "make all" to build all targets marked with [*] '
 	@echo  'For further info browse Documentation/kbuild/*'