[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 <r.bolshakov(a)yadro.com&gt;
---
 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
 
-- 
2.20.1

[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 <r.bolshakov(a)yadro.com&gt;
 ---
  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 <philmd(a)redhat.com&gt;

[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