[build] Centralise dummy architecture-specific headers

Simplify the process of adding a new CPU architecture by providing
common implementations of typically empty architecture-specific header
files.

Signed-off-by: Michael Brown <[email protected]>

Author: mcb30

src/Makefile.housekeeping

@@ -366,11 +366,6 @@ MAKEDEPS	+= arch/$(ARCH)/Makefile
 include arch/$(ARCH)/Makefile
 endif
 
-# Include architecture-specific include path
-ifdef ARCH
-INCDIRS		+= arch/$(ARCH)/include
-endif
-
 ###############################################################################
 #
 # Especially ugly workarounds

src/arch/arm/Makefile

@@ -3,9 +3,9 @@
 ASM_TCHAR	:= %
 ASM_TCHAR_OPS	:= %%
 
-# Include common ARM headers
+# Include ARM-specific headers
 #
-INCDIRS		+= arch/arm/include
+INCDIRS		:= arch/$(ARCH)/include arch/arm/include $(INCDIRS)
 
 # ARM-specific directories containing source files
 #

src/arch/arm/include/bits/acpi.h

@@ -18,6 +18,9 @@ endif
 # EFI requires -fshort-wchar, and nothing else currently uses wchar_t
 CFLAGS		+= -fshort-wchar
 
+# Include LoongArch64-specific headers
+INCDIRS		:= arch/$(ARCH)/include $(INCDIRS)
+
 # LoongArch64-specific directories containing source files
 SRCDIRS		+= arch/loong64/core
 SRCDIRS		+= arch/loong64/interface/efi

src/arch/arm/include/bits/hyperv.h

@@ -3,9 +3,9 @@
 ASM_TCHAR	:= @
 ASM_TCHAR_OPS	:= @
 
-# Include common x86 headers
+# Include x86-specific headers
 #
-INCDIRS		+= arch/x86/include
+INCDIRS		:= arch/$(ARCH)/include arch/x86/include $(INCDIRS)
 
 # x86-specific directories containing source files
 #