Base --disable-mixedabi broken with recent GNUstep Make

[Quentin Mathé]

Hi,

I'm trying to compile GNUstep Base trunk on Debian 8 x64 with libobjc2 1.8, 
clang 3.8.1 and GNUstep Make trunk (configured with --enable-debug-by-default 
--enable-objc-nonfragile-abi --enable-objc-arc).

Compiling Base fails after configuring it with --disable-mixedabi:

"Your gnustep-base was configured for the objc-nonfragile-abi but you are not 
using it now."

This error is printed by the following code from GSVersionMacros.h:

#if     GS_MIXEDABI
#  undef        GS_NONFRAGILE
#  define       GS_NONFRAGILE   0       /* Mixed is treated as fragile */
#else
#  if (__has_feature(objc_nonfragile_abi))
#    if !GS_NONFRAGILE
#      if       defined(GNUSTEP_BASE_INTERNAL)
#        error "You are building gnustep-base using the objc-nonfragile-abi but 
your gnustep-base was not configured to use it."
#      endif
#    endif
#  else
#    if GS_NONFRAGILE
#      error "Your gnustep-base was configured for the objc-nonfragile-abi but 
you are not using it now."
#    endif
#  endif
#endif

Here is a compiler invocation example:

 clang GSObjCRuntime.m -c \
      -MMD -MP -Wall -Wdeclaration-after-statement -DNO_GNUSTEP=1 -DGNUSTEP 
-DGNUSTEP_BASE_LIBRARY=1 -DGNU_GUI_LIBRARY=1 -DGNU_RUNTIME=1 
-DGNUSTEP_BASE_LIBRARY=1 -fno-strict-aliasing -fexceptions -fobjc-exceptions 
-D_NATIVE_OBJC_EXCEPTIONS -D_NONFRAGILE_ABI -pthread -fPIC -DDEBUG 
-fno-omit-frame-pointer -Wall -DGSWARN -DGSDIAGNOSE -Wno-import -g 
-fgnu-runtime -fgnu-runtime -fconstant-string-class=NSConstantString -I../. 
-I../ -I../../Headers -I. -I/home/vagrant/GNUstep/Library/Headers 
-I/usr/local/include -I/usr/local/include -I/usr/local/include 
-I/usr/local/include -I/usr/local/include -I/usr/include/libxml2 
-I/usr/include/p11-kit-1 \
       -o obj/Additions.obj/GSObjCRuntime.m.o


The problem comes from (__has_feature(objc_nonfragile_abi)) returning false, 
even when --enable-objc-nonfragile-abi has been passed to GNUstep Make. 

In March, -fobjc-nonfragile-abi was removed from common.make with this commit 
https://github.com/gnustep/make/commit/9e519435a719163986a2bdede5c9b60b8db9fdd1

If I add it back, (__has_feature(objc_nonfragile_abi)) evaluates to true as 
expected. I tried to replace -fobjc-nonfragile-abi by 
-fobjc-runtime=gnustep-1.8 in INTERNAL_OBJCFLAGS, but  
(__has_feature(objc_nonfragile_abi)) still evaluates to false in this case. Is 
this a bug in clang?

Looks like we should keep adding -fobjc-nonfragile-abi to INTERNAL_OBJCFLAGS in 
common.make, unless there is a better fix.


As a side note, what is the purpose of passing --enable-objc-arc to GNUstep 
Make configure? This doesn't add -fobjc-arc to INTERNAL_OBJC_FLAGS and USE_ARC 
doesn't seem to be used either in GNUstep Make or Base.

Cheers,
Quentin.