[PATCH] build: Allow to use cross C preprocessor

[Roman Bolshakov]

An attempt to cross-compile SeaBIOS on macOS can fail because host C
preprocessor doesn't comprehend the command line options:

Compiling IASL src/fw/acpi-dsdt.hex
cpp -P -MD -MT src/fw/acpi-dsdt.hex src/fw/acpi-dsdt.dsl -o out/src/fw/acpi-dsdt.dsl.i.orig
clang: error: no input files
make: *** [src/fw/acpi-dsdt.hex] Error 1

Signed-off-by: Roman Bolshakov 
---
 Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index d2d11db..909c0a1 100644
--- a/Makefile
+++ b/Makefile
@@ -23,7 +23,7 @@ OBJCOPY=$(CROSS_PREFIX)objcopy
 OBJDUMP=$(CROSS_PREFIX)objdump
 STRIP=$(CROSS_PREFIX)strip
 PYTHON=python
-CPP=cpp
+CPP=$(CROSS_PREFIX)cpp
 IASL:=iasl
 LD32BIT_FLAG:=-melf_i386

[Philippe Mathieu-Daudé]

On 1/25/19 4:55 PM, Roman Bolshakov wrote:
> An attempt to cross-compile SeaBIOS on macOS can fail because host C
> preprocessor doesn't comprehend the command line options:
>
> Compiling IASL src/fw/acpi-dsdt.hex
> cpp -P -MD -MT src/fw/acpi-dsdt.hex src/fw/acpi-dsdt.dsl -o out/src/fw/acpi-dsdt.dsl.i.orig
> clang: error: no input files
> make: *** [src/fw/acpi-dsdt.hex] Error 1
> Signed-off-by: Roman Bolshakov
>
> Makefile | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/Makefile b/Makefile
> index d2d11db..909c0a1 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -23,7 +23,7 @@ OBJCOPY=$(CROSS_PREFIX)objcopy
>  OBJDUMP=$(CROSS_PREFIX)objdump
>  STRIP=$(CROSS_PREFIX)strip
>  PYTHON=python
> -CPP=cpp
> +CPP=$(CROSS_PREFIX)cpp
>  IASL:=iasl
>  LD32BIT_FLAG:=-melf_i386

Reviewed-by: Philippe Mathieu-Daudé

[Paul Menzel]

Dear Roman,

On 01/25/19 16:55, Roman Bolshakov wrote:
> An attempt to cross-compile SeaBIOS on macOS can fail because host C
> preprocessor doesn't comprehend the command line options:
>
> Compiling IASL src/fw/acpi-dsdt.hex
> cpp -P -MD -MT src/fw/acpi-dsdt.hex src/fw/acpi-dsdt.dsl -o out/src/fw/acpi-dsdt.dsl.i.orig
> clang: error: no input files
> make: *** [src/fw/acpi-dsdt.hex] Error 1

Could you please add the Clang version?

[…]

Kind regards,

Paul

[Roman Bolshakov]

On Mon, Jan 28, 2019 at 01:29:14PM +0100, Paul Menzel wrote:
> Dear Roman,
>
> On 01/25/19 16:55, Roman Bolshakov wrote:
> > An attempt to cross-compile SeaBIOS on macOS can fail because host C
> > preprocessor doesn't comprehend the command line options:
> >
> > Compiling IASL src/fw/acpi-dsdt.hex
> > cpp -P -MD -MT src/fw/acpi-dsdt.hex src/fw/acpi-dsdt.dsl -o out/src/fw/acpi-dsdt.dsl.i.orig
> > clang: error: no input files
> > make: *** [src/fw/acpi-dsdt.hex] Error 1
>
> Could you please add the Clang version?

Sure Paul,

$ cpp --version
Apple LLVM version 10.0.0 (clang-1000.11.45.5)
Target: x86_64-apple-darwin18.2.0
Thread model: posix
InstalledDir:
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin

Thank you,
Roman

[Kevin O'Connor]

On Fri, Jan 25, 2019 at 06:55:10PM +0300, Roman Bolshakov wrote:
> An attempt to cross-compile SeaBIOS on macOS can fail because host C
> preprocessor doesn't comprehend the command line options:
>
> Compiling IASL src/fw/acpi-dsdt.hex
> cpp -P -MD -MT src/fw/acpi-dsdt.hex src/fw/acpi-dsdt.dsl -o out/src/fw/acpi-dsdt.dsl.i.orig
> clang: error: no input files
> make: *** [src/fw/acpi-dsdt.hex] Error 1

Thanks, but at high level this change doesn't look correct to me.
(The pre-processor isn't doing anything that is specific to the target
machine.)  If the user has an incompatible cpp then they can directly
change the CPP with: make CPP=/some/path/to/cpp

-Kevin