The efforts we go through by installing a single arch are counter
productive when the base directory already supports them all, and
the arch-specific files are really small. Let's make the "headers"
target simply install headers for all supported archs and stop
trying to build a hybrid "arch.h" file on the fly, to instead keep
the generic one.

Signed-off-by: Willy Tarreau <w@1wt.eu>
---
 tools/include/nolibc/Makefile | 20 ++++++++------------
 1 file changed, 8 insertions(+), 12 deletions(-)

diff --git a/tools/include/nolibc/Makefile b/tools/include/nolibc/Makefile
index c69d7bf60c71e..d5be3d213c885 100644
--- a/tools/include/nolibc/Makefile
+++ b/tools/include/nolibc/Makefile
@@ -24,6 +24,8 @@ Q=@
 endif
 
 arch_file := arch-$(ARCH).h
+nolibc_supported_archs := arm64 arm loongarch m68k mips powerpc riscv s390 sparc x86
+
 all_files := \
 		compiler.h \
 		crt.h \
@@ -81,7 +83,7 @@ help:
 	@echo "Supported targets under nolibc:"
 	@echo "  all                 call \"headers\""
 	@echo "  clean               clean the sysroot"
-	@echo "  headers             prepare a sysroot in \$${OUTPUT}sysroot"
+	@echo "  headers             prepare a multi-arch sysroot in \$${OUTPUT}sysroot"
 	@echo "  headers_standalone  like \"headers\", and also install kernel headers"
 	@echo "  help                this help"
 	@echo ""
@@ -92,18 +94,12 @@ help:
 	@echo "  OUTPUT  = $(OUTPUT)"
 	@echo ""
 
+# installs headers for all archs at once.
 headers:
-	$(Q)mkdir -p $(OUTPUT)sysroot
-	$(Q)mkdir -p $(OUTPUT)sysroot/include
-	$(Q)cp --parents $(all_files) $(OUTPUT)sysroot/include/
-	$(Q)if [ "$(ARCH)" = "i386" -o "$(ARCH)" = "x86_64" ]; then \
-		cat arch-x86.h;                 \
-	elif [ -e "$(arch_file)" ]; then        \
-		cat $(arch_file);               \
-	else                                    \
-		echo "Fatal: architecture $(ARCH) not yet supported by nolibc." >&2; \
-		exit 1;                         \
-	fi > $(OUTPUT)sysroot/include/arch.h
+	$(Q)mkdir -p "$(OUTPUT)sysroot"
+	$(Q)mkdir -p "$(OUTPUT)sysroot/include"
+	$(Q)cp --parents $(all_files) arch.h "$(OUTPUT)sysroot/include/"
+	$(Q)cp $(addsuffix .h,$(addprefix arch-,$(nolibc_supported_archs))) "$(OUTPUT)sysroot/include/"
 
 headers_standalone: headers
 	$(Q)$(MAKE) -C $(srctree) headers
-- 
2.17.5

On 2025-06-29 19:07:31+0200, Willy Tarreau wrote:
> The efforts we go through by installing a single arch are counter
> productive when the base directory already supports them all, and
> the arch-specific files are really small. Let's make the "headers"
> target simply install headers for all supported archs and stop
> trying to build a hybrid "arch.h" file on the fly, to instead keep
> the generic one.
> 
> Signed-off-by: Willy Tarreau <w@1wt.eu>
> ---
>  tools/include/nolibc/Makefile | 20 ++++++++------------
>  1 file changed, 8 insertions(+), 12 deletions(-)
> 
> diff --git a/tools/include/nolibc/Makefile b/tools/include/nolibc/Makefile
> index c69d7bf60c71e..d5be3d213c885 100644
> --- a/tools/include/nolibc/Makefile
> +++ b/tools/include/nolibc/Makefile
> @@ -24,6 +24,8 @@ Q=@
>  endif
>  
>  arch_file := arch-$(ARCH).h

arch_file is unused now.

> +nolibc_supported_archs := arm64 arm loongarch m68k mips powerpc riscv s390 sparc x86

Nitpick:
Instead of having another variable, can we add the arch-foo.h files to
all_files instead? In patch 2 they can be extracted from there with $(filter)?

> +
>  all_files := \
>  		compiler.h \
>  		crt.h \
> @@ -81,7 +83,7 @@ help:
>  	@echo "Supported targets under nolibc:"
>  	@echo "  all                 call \"headers\""
>  	@echo "  clean               clean the sysroot"
> -	@echo "  headers             prepare a sysroot in \$${OUTPUT}sysroot"
> +	@echo "  headers             prepare a multi-arch sysroot in \$${OUTPUT}sysroot"

If multi-arch is the only remaining mode, do we need to mention it?

>  	@echo "  headers_standalone  like \"headers\", and also install kernel headers"
>  	@echo "  help                this help"
>  	@echo ""
> @@ -92,18 +94,12 @@ help:
>  	@echo "  OUTPUT  = $(OUTPUT)"
>  	@echo ""
>  
> +# installs headers for all archs at once.
>  headers:
> -	$(Q)mkdir -p $(OUTPUT)sysroot
> -	$(Q)mkdir -p $(OUTPUT)sysroot/include
> -	$(Q)cp --parents $(all_files) $(OUTPUT)sysroot/include/
> -	$(Q)if [ "$(ARCH)" = "i386" -o "$(ARCH)" = "x86_64" ]; then \
> -		cat arch-x86.h;                 \
> -	elif [ -e "$(arch_file)" ]; then        \
> -		cat $(arch_file);               \
> -	else                                    \
> -		echo "Fatal: architecture $(ARCH) not yet supported by nolibc." >&2; \
> -		exit 1;                         \
> -	fi > $(OUTPUT)sysroot/include/arch.h
> +	$(Q)mkdir -p "$(OUTPUT)sysroot"
> +	$(Q)mkdir -p "$(OUTPUT)sysroot/include"
> +	$(Q)cp --parents $(all_files) arch.h "$(OUTPUT)sysroot/include/"

Can we add arch.h to all_files, to avoid the special case here?

> +	$(Q)cp $(addsuffix .h,$(addprefix arch-,$(nolibc_supported_archs))) "$(OUTPUT)sysroot/include/"
>  
>  headers_standalone: headers
>  	$(Q)$(MAKE) -C $(srctree) headers
> -- 
> 2.17.5
>