Clang 3.4 stdlib.h compile error

Question

I am running into a rather hairy compile issue with Clang 3.4. The code compiles just fine with Clang 3.2 but I want to experiment with some bleeding edge features found only on Clang 3.4.

I installed Clang 3.4 by following the instructions here.

Does anyone have a clue as to why Clang is complaining about stdlib.h? I am using Lubuntu 13.04.

Output from Clang 3.2 -

clang  -v -g -fsanitize=address -fno-omit-frame-pointer -fms-extensions -O0 -o obj/Test.o -Iinc/ -c Test.c
Ubuntu clang version 3.2-1~exp9ubuntu1 (tags/RELEASE_32/final) (based on LLVM 3.2)
Target: i386-pc-linux-gnu
Thread model: posix
 "/usr/bin/clang" -cc1 -triple i386-pc-linux-gnu -emit-obj -mrelax-all -disable-free -disable-llvm-verifier -main-file-name Test.c -mrelocation-model static -mdisable-fp-elim -fmath-errno -masm-verbose -mconstructor-aliases -fuse-init-array -target-cpu pentium4 -target-linker-version 2.23.2 -momit-leaf-frame-pointer -v -g -coverage-file /home/adminuser/project/obj/Test.o -resource-dir /usr/bin/../lib/clang/3.2 -I inc/ -fmodule-cache-path /var/tmp/clang-module-cache -internal-isystem /usr/local/include -internal-isystem /usr/bin/../lib/clang/3.2/include -internal-isystem /usr/include/clang/3.2/include/ -internal-externc-isystem /usr/include/i386-linux-gnu -internal-externc-isystem /usr/include/i686-linux-gnu -internal-externc-isystem /usr/include -O0 -fdebug-compilation-dir /home/adminuser/project -ferror-limit 19 -fmessage-length 0 -fsanitize=address -mstackrealign -fms-extensions -fmsc-version=1300 -fobjc-runtime=gcc -fdiagnostics-show-option -o obj/Test.o -x c Test.c
clang -cc1 version 3.2 based upon LLVM 3.2svn default target i386-pc-linux-gnu
ignoring nonexistent directory "/usr/bin/../lib/clang/3.2/include"
ignoring nonexistent directory "/usr/include/i686-linux-gnu"
#include "..." search starts here:
#include <...> search starts here:
 inc
 /usr/local/include
 /usr/include/clang/3.2/include
 /usr/include/i386-linux-gnu
 /usr/include

Output from Clang 3.4 -

clang -v -g -fsanitize=address -fno-omit-frame-pointer -fms-extensions -O0 -o obj/Test.o -Iinc/ Test.c
Ubuntu clang version 3.4-1~exp1 (trunk) (based on LLVM 3.4)
Target: i386-pc-linux-gnu
Thread model: posix
Found candidate GCC installation: /usr/bin/../lib/gcc/i686-linux-gnu/4.7
Found candidate GCC installation: /usr/bin/../lib/gcc/i686-linux-gnu/4.7.3
Found candidate GCC installation: /usr/bin/../lib/gcc/i686-linux-gnu/4.8
Found candidate GCC installation: /usr/bin/../lib/gcc/i686-linux-gnu/4.8.1
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/4.7
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/4.7.3
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/4.8
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/4.8.1
Selected GCC installation: /usr/lib/gcc/i686-linux-gnu/4.8
 "/usr/bin/clang" -cc1 -triple i386-pc-linux-gnu -emit-obj -mrelax-all -disable-free -disable-llvm-verifier -main-file-name Test.c -mrelocation-model static -mdisable-fp-elim -fmath-errno -masm-verbose -mconstructor-aliases -fuse-init-array -target-cpu pentium4 -target-linker-version 2.23.2 -v -g -coverage-file /home/adminuser/project/obj/Test.o -resource-dir /usr/bin/../lib/clang/3.4 -I inc/ -internal-isystem /usr/local/include -internal-isystem /usr/bin/../lib/clang/3.4/include -internal-isystem /usr/include/clang/3.4/include/ -internal-externc-isystem /usr/include/i386-linux-gnu -internal-externc-isystem /usr/include/i686-linux-gnu -internal-externc-isystem /usr/include -O0 -fdebug-compilation-dir /home/adminuser/BuildFW/test/GlassCubeAssembler_C -ferror-limit 19 -fmessage-length 0 -fsanitize=address,init-order -mstackrealign -fms-extensions -fmsc-version=1300 -fobjc-runtime=gcc -fobjc-default-synthesize-properties -fdiagnostics-show-option -vectorize-slp -o obj/Test.o -x c Test.c
clang -cc1 version 3.4 based upon LLVM 3.4 default target i386-pc-linux-gnu
ignoring nonexistent directory "/usr/bin/../lib/clang/3.4/include"
ignoring nonexistent directory "/usr/include/i686-linux-gnu"
#include "..." search starts here:
#include <...> search starts here:
 inc
 /usr/local/include
 /usr/include/clang/3.4/include
 /usr/include/i386-linux-gnu
 /usr/include
End of search list.
In file included from Test.c:4:
/usr/include/stdlib.h:69:23: error: expected member name or ';' after declaration specifiers
    union wait *__uptr;
    ~~~~~             ^
1 error generated.

Answer 1

The issue is that you're using -fms-extensions, which enables MS extensions, including a __uptr keyword. Inside stdlib.h, __uptr is used as an identifier:

union wait *__uptr;

... which is incompatible with the MS extension.

Alp Toker has added a workaround for this in clang trunk in upstream r195710, and the fix will be in the Clang 3.4 release.

Answer 2

This was http://llvm.org/PR17824 and was fixed by Alp Toker in Clang r195710: http://llvm.org/viewvc/llvm-project?rev=195710&view=rev