[klibc] Kbuild: Remove KLIBCKERNELOBJ variable

Since the UAPI/KAPI header split in Linux 3.7, we have needed
KLIBCKERNELSRC to point to the installed UAPI headers.  This makes
KLIBCKERNELOBJ and the extra header directories based on it completely
redundant.

Link: https://www.zytor.com/pipermail/klibc/2019-January/004031.html
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
diff --git a/Makefile b/Makefile
index 4386135..a11d1e6 100644
--- a/Makefile
+++ b/Makefile
@@ -11,7 +11,6 @@
 export KLIBCINC := usr/include
 export KLIBCOBJ := usr/klibc
 export KLIBCKERNELSRC ?= linux
-export KLIBCKERNELOBJ ?= $(KLIBCKERNELSRC)
 
 export VPATH := $(srctree)
 
@@ -135,7 +134,6 @@
 	@echo
 	@echo	'Build options:'
 	@echo	'KLIBCKERNELSRC - Path to a configured linux tree'
-	@echo	'KLIBCKERNELOBJ - Path to kernel output dir (defaults to KLIBCKERNELSRC)'
 	@echo	'make V=0|1 [targets] 0 => quiet build (default), 1 => verbose build'
 	@echo	'make V=2   [targets] 2 => give reason for rebuild of target'
 	@echo
diff --git a/scripts/Kbuild.klibc b/scripts/Kbuild.klibc
index 35c375e..de1cd27 100644
--- a/scripts/Kbuild.klibc
+++ b/scripts/Kbuild.klibc
@@ -78,7 +78,7 @@
 KLIBCCFLAGS       :=
 
 # Defaults for arch to override
-KLIBCARCHINCFLAGS = -I$(KLIBCKERNELOBJ)/arch/$(KLIBCARCH)/include
+KLIBCARCHINCFLAGS =
 
 # Arch specific definitions for klibc
 include $(srctree)/$(KLIBCSRC)/arch/$(KLIBCARCHDIR)/MCONFIG
@@ -113,10 +113,8 @@
                     -I$(KLIBCINC)
 # kernel include paths
 KLIBCKERNELSRC	 ?= $(srctree)
-KLIBCKERNELOBJ	 ?= $(objtree)
-KLIBCCPPFLAGS    += -I$(KLIBCKERNELSRC)/include				    \
-                     $(if $(KBUILD_SRC),-I$(KLIBCKERNELOBJ)/include2 	    \
-		       -I$(KLIBCKERNELOBJ)/include -I$(srctree)/include)    \
+KLIBCCPPFLAGS    += -I$(KLIBCKERNELSRC)/include		\
+                     $(if $(KBUILD_SRC),-I$(srctree)/include)  \
 		     $(KLIBCARCHINCFLAGS)
 
 # klibc definitions
diff --git a/usr/klibc/arch/i386/MCONFIG b/usr/klibc/arch/i386/MCONFIG
index bfec004..0704669 100644
--- a/usr/klibc/arch/i386/MCONFIG
+++ b/usr/klibc/arch/i386/MCONFIG
@@ -31,6 +31,3 @@
 # calls, and work on the memory models for this architecture
 # 96 MB - normal binaries start at 128 MB
 KLIBCSHAREDFLAGS	= -Ttext-segment 0x06000000
-
-# Asm includes for i386 are in the merged x86 tree
-KLIBCARCHINCFLAGS = -I$(KLIBCKERNELOBJ)/arch/x86/include
diff --git a/usr/klibc/arch/ppc/MCONFIG b/usr/klibc/arch/ppc/MCONFIG
index 6630df7..46c5923 100644
--- a/usr/klibc/arch/ppc/MCONFIG
+++ b/usr/klibc/arch/ppc/MCONFIG
@@ -22,8 +22,5 @@
 # to +/- 16 MB
 KLIBCSHAREDFLAGS     = -Ttext 0x0f800200
 
-# The kernel so far has both asm-ppc* and asm-powerpc.
-KLIBCARCHINCFLAGS = -I$(KLIBCKERNELOBJ)/arch/powerpc/include
-
 # The asm include files live in asm-powerpc
 KLIBCASMARCH	= powerpc
diff --git a/usr/klibc/arch/ppc64/MCONFIG b/usr/klibc/arch/ppc64/MCONFIG
index 1331e05..a147593 100644
--- a/usr/klibc/arch/ppc64/MCONFIG
+++ b/usr/klibc/arch/ppc64/MCONFIG
@@ -20,8 +20,5 @@
 # to +/- 16 MB
 KLIBCSHAREDFLAGS     = -Ttext 0x0f000200
 
-# The kernel so far has both asm-ppc* and asm-powerpc.
-KLIBCARCHINCFLAGS = -I$(KLIBCKERNELOBJ)/arch/powerpc/include
-
 # The asm include files live in asm-powerpc
 KLIBCASMARCH	= powerpc
diff --git a/usr/klibc/arch/riscv64/MCONFIG b/usr/klibc/arch/riscv64/MCONFIG
index 38703d9..34f0774 100644
--- a/usr/klibc/arch/riscv64/MCONFIG
+++ b/usr/klibc/arch/riscv64/MCONFIG
@@ -18,5 +18,3 @@
 
 # Normal binaries start at 64 KB, so start the libary at 2 MB.
 KLIBCSHAREDFLAGS  =-Ttext 0x00200200
-
-KLIBCARCHINCFLAGS = -I$(KLIBCKERNELOBJ)/arch/riscv/include
diff --git a/usr/klibc/arch/x86_64/MCONFIG b/usr/klibc/arch/x86_64/MCONFIG
index 606f041..c5f2fa2 100644
--- a/usr/klibc/arch/x86_64/MCONFIG
+++ b/usr/klibc/arch/x86_64/MCONFIG
@@ -36,6 +36,3 @@
 # in a broken layout with binutils 2.30.  Since there's no
 # architectural page size betwen 4 KB and 2MB, set it to 4 KB.
 KLIBCSHAREDFLAGS     = -Ttext-segment 0x00200000 -z max-page-size=0x1000
-
-# Asm includes for x86_64 are in the merged x86 tree
-KLIBCARCHINCFLAGS = -I$(KLIBCKERNELOBJ)/arch/x86/include